How long did it take another developer to match what Bizarre managed to do with an Xbox 360 in 2007 with PGR 4? The fact is PGR4 is an old game yet it still mixes with the best console racing game made today. 30fps was a smart trade off by Bizarre in both PGR 3 and 4 as well as Blur given the 60fps Forza has very noticable aliasing issues when racing whilst Horizon has a decent level of anti-aliasing because of the lower framerate. Further, I've never read anyone complaining about Dirt, Grid, F1 or Split/Second looking like shite even though these 4 games run at 30fps.
"
Regardless of how optimised your engine is you can, by definition, render twice as much detail at 30FPS as at 60FPS. For Split/Second we felt that the consumer experience would be best enhanced by having more detailed environments, more physics, more VFX and explosions, more lighting and more impressive Power Plays" -
http://www.eurogamer.net/articles/digitalfoundry-split-second-tech-interview?page=2
FWIW, I prefer to run my PC racing sims at 60fps or more; it's a very difficult task to achieve on the ancient Xbox hardware with a decent level of AI cars. 60 fps with 4xMSAA (or better) and 16xAF should be attainable on new console hardware and hopefully Lucid and other ex-Bizarre Creations studio developers will be making racing games.