No. Just no.
For one thing, PC games sell fine. Granted, they don't make as much money as console games, but multi-format games are just as popular on PC as their console equivalents. The real reason PC sims don't sell as well is because... they're sims.
Look around you. The gaming industry is becoming more and more dominated by copy-cat games, games aimed at the 'casual gamer', and games that are easy to churn out as quickly as possible to capitalise on whatever fad is currently the most popular. The perceived demand is for pick-up-and-play games that can be finished in 20 hours or less, not for demanding simulators with learning curves which can take potentially days/weeks (if not months) to master. Simulators have never sold as well as 'regular' games, and they never will. But communities of fans such as RD will make sure they sell enough to make them worthwhile for the developers.
As for switching to PS3, you must be joking. GT5 is selling well, and I like the game. However, it is in not a true simulator and lacks almost everything you get in games such as Race 07 and rFactor. Nearly every 'complaint' posted about GT5 is something which has had to be compromised because it's on a console rather than a PC. There's a reason for the compromises... consoles can't cope. Even if they could, they just don't have the versatility of PCs. You use mods for Race 07, right? Wouldn't be any on PS3.
Sims are and should always be the domain of PC games.