They do since it costs them $ but I'm all for them remastering PS3 games ...

You may have a point about the PS2 b/c on PS4. Technically there is nothing stopping Sony from doing like MS is doing, i.e. have the PS2 disc loaded to download and play the digital version of the PS2 game. If the PS2 disc isn't in the digital game won't start. Yes, the trophies add a cost since for each game they have to go through the locations where the trophies will pop up , the higher resolution not much, is already in the emulator and the games had to be tested anyway even at standard resolution.

Regarding the PS3 b/c instead you well know why it isn't there. The Cell CPU is a beast and it can't be emulated by the weak AMD CPU in the PS4. To add the PS3 b/c by HW would have raised the cost of the PS4 consistently. Sony took that route already with the PS3 and the market response had been negative. I strongly doubt a $500 PS4 with HW PS3 b/c would have sold 34 million or so in 2 years.

Well, that's not entirely true honestly. They haven't always hated BC, and they were pretty staunch supporters of it even to the point of putting the Emotion Engine and RSX chip (PS2 internals) on the Circuit board of the launch PS3 models. People didn't want it, or couldn't afford it. It cost Sony a great deal of money (granted, that wasn't just emulations fault, however removing it allowed them to drop the price very quickly) to add into the PS3. Having PS3 BC on the PS4, and I could be wrong here, but I believe it would require a Cell Processor on the PS4 mobo, or a complete rewrite of the software due to how PS3 games had to have the vast, vast majority of tasks traditionally run on the GPU offloaded to the Cell's SPE's.

As for PS2/PS1 BC, not sure about that. But, I wonder if they spent most of the design phase of the PS4 working with Devs on what they wanted moving forward, and tailoring the architecture to their needs, which didn't include BC.

Your analogy is pretty bad, VHS is a format that requires a reworking of the whole device, where ps4 being able to play ps1 or ps2 is software related. More suitable analogy would be if you want your Blu-ray player be able to play CDs or DVDs, and most people would say yes. 

It is accepted because the market leader doesn't do it, however it is something that the consumers would welcome. If it wasn't a feature people wanted, they would not rerelease old ps2 digitally. 

Doesnt all BR players play DVDs?

Yes, and thats why he went with the VHS Analogy. 

Add: Large percentage of them do. 

Says home console with an "s" at the end of console. Meaning more than 1 Sony home console did not have BC. Let's go through these plot points in order, shall we.

1. PS1. No BC for obvious reasons, so that not included AT ALL.

2. PS2. Has BC. Can play PS1 games.

3. PS3. Has BC. Can play PS1 and PS2 games.

4. PS3. Later, BC was removed on newer PS3 consoles for PS2 games. Can still play PS1 games.

5. PS4. No BC unless paying throught PS Now for PS3 games and on PS Store for PS2 games.

Now...for you to say you HATE Sony's home consoles mainly because of 1 console is just silly. They had BC for all their home consoles except for 1...the PS4.

Note: Yes, I read the whole thing, but...the post speaks for itself.

Nope!

Ps2 and early PS3 all had BC. Only pa4 doesn't. And the 360 and xb1 BC is/was very limited it's almost not worth talking about.

BC is only useful for launch when not many games are available or consoles with small libraries.

That boat has already sailed. The PS4 doesn't have true BC and it never will so please get over it. Ever since MS introduced very limited BC to the xbox one to add more value to console to stay competitive, some act like BC is a must have or the greatest thing ever when hardly anyone was talking about BC before. No, it's not.

It's a nice feature to have but I didn't buy a PS4 to play PS3 games or many older games. It's fun to play an old game once in while when the mood strikes but it's not essential to why I bought the console which was to experience current gen games and plenty of new IPs.

People showed Sony what they thought of BC when the PS3 first came out. The console started to sell when BC was removed from the console along with other features to drop it's price. Hmm I wonder why sony chose not to have BC this time around.... Sony designed the PS4 well and had it at the perfect price point which annihilated it's competition on sales.