Strange logic, I mean you can still buy Gameboy and GC games from ebay, it's not as if you cannot actually acquire a copy of the games? you can even get them new and sealed if you want to break that Nintendo seal on the box.
For myself for convenience sake I pirate all the old machines, Arcades, consoles , pretty much everything I can get my hands on a GoodSet of games for I'll store on my media PC, while I still own every title I've ever bought (with 1-2 exceptions) I don't really enjoy spending the 30 mins at times to get my NES to stop loop resetting to get a game of megaman 2 in, so I'll often fire up the emulated version of it instead and sit back on the couch with a DS3 wirelessly rather than be stuck with the tiny short cables on the NES pads.
For consoles which have no hardware issues now though I'll almost always play them on the original hardware as long as the battery back up in the titles is still fine (my copies of Secret of Evermore and Story of Thor have sadly both lost the ability to save, so emulation it is)
Not going to justify my actions with statements like if companies would sell me NES titles on a new system I'd buy them up.... I just wouldn't, I still have my original carts for all the games I love on that system so I wouldn't buy them again unless they were things remastered like on the GBA versions of Mario Bros, or the SNES Super Mario All Stars, but I wouldn't buy a ROM from the eshop of a game I have access to... that said on the Vita I've bought a ton of PSone titles which I do have the discs to also... but that is because the Vita never leaves my side and it was worth doing that for the convenience / in ability to hack that console.
Oh and Nintendo annoyed me into 3DS modding, when the SNES titles were shown for the 3DS eshop... but then were only playable on the NEW model of 3DS I thought fuck that, surely the 3DS is capable of running SNES roms if it can run games like resident evil revelations so I started to look into modding the system to be able to do just that, who could have guessed the powerhouse that is the 3ds could emulate the 2.79mhz snes cpu lol.
Cart even fits perfectly into it!
Why not check me out on youtube and help me on the way to 2k subs over at www.youtube.com/stormcloudlive
