IMO the true test of a console's greatness, is how they hold up years later. As a console gets older, fewer, and fewer games in its library are considered fun by modern standards. And some of those games get remakes that make the original completely obsolete (SSF2THDR is a great example of this.) Then there's games that were meant to be played online, and had their servers shut down. Or a game that is still fun, isn't as good because the graphics aged with zero grace. As soon as a successor is announced game prices seem to plummet, for a system. There's usually a period where a system is considered old, but not classic, so prices bottom out. Eventually prices go back up as working discs, and carts dwindle, and as those systems are considered retro. Once a console is two generations in the rearview mirror it has entered its golden years. 

I'm bringing up this topic, because I just streamlined my PS3 collection. Some games on that system were too old to keep due to the list of reasons listed above. Fallout 3, Skyrim, Dragon Age Origins, and the first two Dark Souls games were sent to the local trade-in shop. The Bioshock Trilogy was swapped out for the PS4 Remaster. Some games never ran very well on the PS3, and they run especially poorly, in comparison to modern systems. Other games like The Orange Box, Mass Effect series, and Dragon Age II were kept due to the need to have DRM free copies of the game. Games made with the PS3 in mind, and exclusives were all kept. 

Anyway, this makes me think about how other systems have aged, and how the PS4/XB1 might age. I'll post my thoughts on a few sysetms, and maybe some other people will be willing to post theirs. I thought it would be a thought provoking discussion, and a bit of philosophy on growing old. I'm 34, and sometimes it hurts to see things change so much that I hardly recognize the current gaming landscape. 

NES

I think most NES games hold up decently well. For the NES there's the obvious Super Mario Bros. 3. And then there's a little gem called River City Ransom. Hands down the best 2D beat'em up ever made. It has a plethora of moves that dwarf even games made years later. You can level up your fighters, and customize them as you play the game. Old JRPGs like Final Fantasy 1 Don't hold up very well, but DragonQuest 4 is good for its time if you can find it. But that got remade on the DS. 

SNES

 2D sprites hold up well, and Indie developers still struggle to match the best games that these systems have to offer. Movie Tie-Ins were yet to be considered Shovelware, so the SNES boasts quite a few quality games like Aladdin, and The Lion King. There are five titles on the SNES that I consider to be timeless classics. I refer to them as the big 5. They are Chrono Trigger, Final Fantasy 3, Super Mario World, Super Metroid, and A Link to the Past. Secret of Mana, Yoshi's Island, and Super Mario RPG also hold up fairly well, but aren't pure classics.

MegaDrive/Genesis

 I have a small but good Genesis collection. Four Sonic games, Thunder Force series, Contra Hard Corps, Castlevania Bloodlines, and good RPGs like Phantasy Star IV, and Shining Force II. IMO the Contra and Castlevania games for Genesis are just better than the SNES versions. They were all made after the SNES versions, so just had smoother gameplay elements. Other games like Kid Chameleon and Ecco are just old now. KC lacks save points, and is brutally hard. Ecco suffers from a lack of analog control in a game where you can Swim in 360 degrees. X-Men 2 has to be one of my favorite Genesis games. It's a platforming hack'n slash with a good list of characters to choose from. Wolverine is hilariously OP in this game. I love the Genesis cases, and wish SNES had them. 

PS1

The only PS1 games that truly hold up anymore are the RPGs, and a few Konomi games. But there's enough here to build a decent collection of games that are still enjoyable. Final Fantasy VII pretty much takes everything from FF3 on SNES and copies it, with a few changes here and there. Square had a heyday with experimentation during the PS1 years, so there's lots of hidden gems from that company. Atlus and other JRPG devs didn't get coverage so there's a lot of hidden gems from them too. 

PS2

 PS2 still holds the record for highest selling console of all time, and it supported a ton of AA developers that died out in the PS3/360/Wii era. The platformers on the PS2 are still fun, mostly because everybody except Nintendo and Insomniac gave up on making 3D platformers over ten years ago. I still think Ace Combat and Devil May Cry have their best entries on PS2. PS2's cases are really heavy duty compared to modern day cases. They are fun to collect. 

360

This was my first system of the 7th generation. It plays a lot of multiplat games better than the PS3, but really lacks exclusives. Aside from Halo , Gears, Fable II, and Viva Pinata there's little on it that PS3 doesn't also play. 

PS3

Overall a good system that plays quite a few games that are either still exclusive to the system, or only really got a resolution upscale version on PS4. Some games like Mass Effect 1-3, Skyrim, Dragon Age, and Fallout just don't play very well at all.

I still play my N64 now and then. I Stopped playing Ocarina in it since I got OoT 3D on 3DS. My PS2 still essential since I collect PS1 RPGs. The Dreamcast didn't age well but its still my place to go for Grandia 2 playthroughs since the PS2 port is utter crap. Now that the game will be remastered on Switch I Guess my DC will be put to rest, unless I want to Play Skies of Arcadia again. My point is all consoles become obsolete eventually if you can find ways to play their games on modern platforms. Certain Games can be ageless though.

Except for speedrunning them, I don't see anymore interest to play these old games (sub 2013 for example). Or, just for 1-2 hours of nostalgia.

I played a ton of NES games back in the day, but I am still getting into the gems on the SNES and Genesis. These are great systems. I'm not too interested in generation 5 at the moment, but the games that look interesting to me (that I might actually play one day) are either RPGs or 2D games like Symphony of the Night.

There are also all of the games on handhelds over the years. There are a lot of great games there that I am still discovering.

I don't get how your conclusion about the PS4/XB1 can be so different when they share 95% of their libraries, and are so similar.

If too many games require an online connection on Xbox One, the same has to be said for PS4.

Wow, I literally couldn't disagree with you more. Not only is it insane to me to combine both consoles instead of looking at how they stand by themselves but ignoring the original PlayStation's library is ridiculous. Only RPGs hold up?. What the fuck. I have so many games that I still play and hold up from that era. 

A short list just because I could spend all day listing great stuff to play for the PS1: Tenchu, Parasite Eve 1 and 2, Dino Crisis 1 and 2, RE1-2-3 (Saturn has 1 and the N64 has 2 but neither of them have the complete trilogy), Metal Gear Solid, Castlevania SOTN (the Saturn port sucked), Tekken 3, the Crash trilogy + Crash Team Racing, Silent Hill (which is the best horror game ever made in my opinion). I could go on and on. You are entitled to your opinion of course but I would play any of those over anything on the NES or SNES.

Had a friend play Tenchu once while I watched. IMO it was completely outdated. The Goldeneye of stealth games. I don't know much about Parasite Eve, or Dino Crisis, so I'll take your word for it. RE has a GC remake that blows the original out of the water. RE2 is getting a remake, and RE3 was on 6th gen systems with better graphics. Metal Gear Solid has a much better GC version. SoTN holds up for sure. How did I forget about that one? Never been a fan of Tekken, but I have it on the PS2 and plan on giving it a try eventually. Crash and Spyro have remakes that are just better than the originals. 

Anyway, if I see Dino Crisis or Parasite Eve games for sale I'll buy them and give them a shot. 

The OP lost me when all Sega systems, over a nearly 20 year period, were lumped together. Compound that with combining PS1 and PS2, and then speculating about the future of XB1 and PS4 in a thread about how old systems have aged, and I just can't wrap my head around this thread.

It's mainly the 30 quality games that PS4 has, but XB1 will never get. If you ignore the mountains of shovelware, and just look at quality games the XB1 is severely lacking. But if you include the shovelware, then yes they have 95% the same library. 

Most of the XB1's exclusives like Forza, Gears, and Halo require an online connection to enjoy the bulk of the game. The same isn't true for Horizon, GoW, Uncharted, etc. Sony's exclusives still focus on single player. 

Not even close to being true. Exclusives this gen make up for barely anything (in quantity), even if you only count quality titles.