One consensus is that Carvana/Vroom/Shift are buying cars at a loss to try and capture market share. Carmax has more of a track record so they might be getting a better shake like your experience. It could also be you calling personally that unlocked the lien, where the other companies don't work that way.
Some manufacturers like Volvo aren't letting you out of the lease early unless you're leasing another Volvo.
They absolutely are. Where I live, these companies are (and have been before COVID) paying well above market rates for newer used cars from private sellers. On the flip side, all of your typical auto sales rags and sites that used to have listings from private sellers and used car dealerships are now mainly carvana listings.
When you read the fine print, the residual value only applies to the owner. The bank can charge whatever it wants to everyone else, or deny the purchase altogether.
I'm in this situation and it's getting strange if your car is leased. Carvana and the like were offering me thousands more than the buyout amount. Like $5,000 at one point.
But now the automakers and their banks are shutting off 3rd party purchases, meaning the only parties that can buy the car off the lease are you and the dealer. And the dealer has no car on-hand to replace the one you plan to sell back, or if they do they want thousands over MSRP because that's what the market is bearing. So it's a wash.