I think the production of games for PS3 and Xbox 360 gen would dwindle eventually as game devs would eventually move to work on the current tech/engine like Unreal 4.
Personally, this forced thing irks me. Seriously? They are desperate...for money. Add a feature to an already existing game but have it only playable on next gen consoles? Sounds like a mere cash grab to me. Even with visual improvements. If you don't have the game yet, it's fine. If you can't keep your old console, that's also fine and dandy but I guess to each his own and I respect that. If the game is an improvement also in gameplay/fixed issues then it's a win-win situation for the person. I also respect die hard fans as I'm one too. I have religiously bought every Tekken game Namco has released on different platforms over the years.
As for me, I would only join the next gen if I see new games, not another remaster or enhanced edition of an existing game. I didn't buy Revelations for PS3/Xbox just for Rachel Foley in Raid Mode because I already have the game on 3DS (with no Rachel). I bought Devil May Cry HD and FFX/FFX-2 HD (just for the Last Mission) because of the nostalgia factor and I was merely curious. It's different compared to the enhanced editions today because PS2 to PS3 had a huge leap in graphics compared to PS3 to PS4. Well almost because it still looks old school and sometimes you see that they didn't cleanup some parts (a RE2 and FF7 remake is another story). I didn't buy KH 2.5 Final Mix HD though because I already saw the new content on youtube and I still have my old copies (PS2 KH 1 and 2 and BBS on PSP). No new stuff storywise because we have KH3 on the way. I do think that the 1.5 and 2.5 collection is good for those newcomers to the series. In short, I won't buy Tomb Raider (2013) game again for my PS4 because I already have one on my PS3.