I believe Lyft has a rental program. From what I've heard, it's basically indentured servitude for the drivers.
I heard at one point it was like $400 a month but that included mileage and you weren't locked into a long term lease. The ones sitting on the lot may be the drivers that got out after not making enough money.
I also heard that there was a reason some drivers didn't have cars and the accident/loss rate was higher with those drivers so those programs may just be winding down which may also explain the cars on the lot.