The one constant in the video game market and video game wars is the death of older systems. As technology advances and bigger, better things can be done, developers and publishers rely more on new systems for better games and more revenue.
Is it fair? Only in the sense that the game developers are able to provide us (usually) with higher-quality games. It's not entirely fair to consumers when console manufacturers cram their systems full of all sorts of expensive, high-end equipment and force us to pay ridiculous price tags to jump on the new wagon. Game consoles that can keep the lower price tag will be more appealing.
I feel your pain with the latest batch of new consoles, as two of the three require an upgrade to more than the game console itself, often requiring high-definition televisions to make the games playable, but again, as technology advances, so must we. I doubt you're still playing NES games on a nine inch black and white television. That generation died a long time ago.
New games are not made for old systems because those systems cannot handle the games. If you want new games, you need a new system. If you want to keep playing on your old system(s), then take the time to find the best games for your system(s) that have been released already.