Not many people have that much money. Yes you can rent or play in friends house, but its only temporary and no way to enjoy them fully. Whats next? Piracy?
No, not piracy, because the real meat of the cost is the consoles/PC. If you can afford the hardware, you can afford the games quite easily.
I think it's a fair assumption that anyone that has a console has a PC already, because a console is a luxury item with a single purpose and a PC is a multipurpose tool that can be used for both entertainment and work.
It's not hard or terribly expensive to make a PC capable of playing games at a reasonable level, and Steam makes the games pretty affordable if you're smart about it. The only sim game that's actually expensive is iRacing, and that's only if you somehow feel like you need all the content. At the basic level it's about $10 for a year of racing if you take advantage of all the deals each year.
PS3s and X360s are cheap at the moment. If you take the gamble on getting one used they're even cheaper. If you're paying more than $20 for any of the games on them you're getting ripped off. I think I got Forza 2, 3 and 4 for $30 total, and that was a year and a bit ago.
The new consoles are expensive, so I can see the point there. But that's one game you're missing out on (two if you count Horizon). Not worth the money.
PC/PS3/360 have games that are worth playing. Even if you're stuck on PS3 somehow, there's still games other than GT that are worth the time and effort, and like I mentioned before used games are not expensive.
PD has been promised it in their website since launch. Now? After 10 months? Thank god I have other games.
The irony of pointing out that people don't have money for other games and then thanking god that you have other games...
You may have noticed that I'm as vocal as anyone about PD and their bollocks. If you haven't, then look at my recent posts. However, I still don't agree with the attitude that GT should be great because it's the only game that people will ever need. It's always going to be interesting, useful and fun to see how other development teams approach the same problems. Yes, there are costs associated with playing more games, but they're much more reasonable than you think if you're smart about it.
If you're serious about sim racing, you've probably invested in a wheel. If you're able to sink that much money into gaming, then you're able to at least make a start on exploring what else is available in the sim racing market. If you want to start free, then I think there are demos for Live for Speed and rFactor 1 still, and most of the Simbin games can be had for next to nothing on Steam.