Right so back in early 2020 I had bought a compact car as an ex-fleet vehicle from Hertz. Spent about $13k after taxes. We'd just moved back to the States from overseas and needed a car in a hurry. Later in the year, there were some great deals on Chevy Bolts, and we'd really wanted an EV, so we got one of those. The dealer we bought the EV from gave us a lousy trade-in offer, so I shopped around to find a dealer who would buy the old car for a better price...best offer was around $12k, if I recall correctly. All of this was before the car shortage began. I was about to do the deal when I saw an ad for this rental program, and I thought what the hell, let's see what happens.
They promised a minimum of about $6k in revenue over the course of a year, provided insurance, and covered maintenance. My car still had a bit of a year left on its bumper to bumper warranty, so I wasn't concerned about a major repair (which would have been at my expense). I expected the car to be worth less after the year due to depreciation and wear-and-tear, especially if any accidents occurred. But my risk analysis suggested I would be unlikely to do worse than break even if things went poorly, and if things went well, I would come out ahead by a few thousand. Also, and this is important: I had zero emotional attachment to the car and zero dependance on it.
I earned about $5500 in the six months before the incident (much more than the minimums - rental car demand has been high generally). The incident turned out to be somebody vandalized the car so extensively it was beyond repair, even though the market value of the car had risen to almost $18,000 (I'll leave it to your imagination how bad the vandalism must have been). But the company and their commercial insurance were great, and I obviously got lucky that the payout was more than I had been about to sell the car for - in some sense it was ideal because I didn't have to deal with taking custody of the car back and trying to sell it down the road.
As for repeating the process and/or scaling, yes I would definitely do it again (only with another car I didn't mind losing). It was a mostly passive enterprise on my part. In fact, I began shopping around for a second car to put to work earlier in the year. But by then the car shortage had started, and here's where it did not work in my favor: I would have had to overpay for a used car now, and I figured it was likely prices would crash back down by the time it came to sell, on top of expected depreciation, erasing a lot of the potential profit. So I'll look into it again in the future when the market is normal again.