New TV makes games look terrible

i recently had my 40something inch 720p plasma die on me. I replaced it with a 50 inch 1080p LED. Obviously differences in contrast and brightness aside, now anything not natively rendered in 1080p looks fuzzy with lots of jaggies. This makes pretty much everything I own on PS3 look bad and most ps4 games running in 900p (AC Unity) which previously looked very crisp now look terrible to the point of where it is distracting.

I mean, the drop in quality makes sense, but at this point, I wonder why anyone who mainly plays games would want 1080p with so few titles natively rendered at that resolution.