I hear ya, very much so. But as a consumer that's not something that I should be concerning myself with. As a consumer, I want the best value for my dollar, period.
If there's such a huge latent demand for this stuff (game rentals), and the success of GameFly seems to indicate that there is, then that SHOULD be a reflection of issues facing the gaming industry at large. Instead publishers just paint a big "bullseye" on the rental business.
The success of these services shows, to me, that many gamers are simply voting with their dollars. They're saying "yes, I enjoy Yakuza. I want Yakuza. But $50 is too much."
There is a problem with videogames in general, and gamers' rental enthusiasm isn't a cause of it, it's a reflection of it.
As for RPGs, I stand by my point. By renting and not buying, I'm telling publishers that the lack of replay incentive cost them my money. Maybe the "standard" for RPGs should be to serialize them, or something. Just one potential solution.
Or imagine this: through the wonders of digital distribution, publishers can handle "rentals" themselves.
I can download cloning clyde and own it forever for a $10 flat fee, or I can "subscribe" to Cloning Clyde and have access to the full version for say $6/month.
When boxed games go digital as well, it could be the same principal. A single play through of FFXV could be $28, and owning unlimited access to the title for all-time would be the standard $50 - the equiv. of buying it in-store.
There's solutions out there to the issues facing publishers, but it seems most of them would rather bury their heads in the sand.