After the first owner is done leasing them <insert middle men here> they get sold on used car lots.
I am of the opinion that the majority of modern cars produced today - especially as you go higher up the price/luxury spectrum - are disposable appliances designed for obsolescence. The base mechanical bits might continue to function fine, but all the fancy technology won't be so fancy after 5 years, and certainly not 10 years.
I think Teslas actually let you upgrade the CPU on the infotainment system (correct me if wrong)? Plus wider spread and use of CarPlay/Android Auto bakes in a little bit of future-proofing.
Component failures are definitely a concern though, and incidental or intentional software failures via OTA, since either may be unrecoverable.
Cars with zero electronic bits other than the radio? Like what models? Cars from the 1980s that come to my mind were extensively computerized.
After I checked the history, it appears that electronic (vs. mechanical) fuel injection came into vogue starting around 1980.
I have a late 80s car, that while primitive in many ways has lots of computers, which can have solder joints fail, so electronics repair is becoming a part of maintaining a "classic car".
(P.S. I am equating your use of "electronic" with "digital", but I think there may have been early examples of analog electronics - Bosch L-Jetronic for example)
I think typically lease returns are sold as [brand] certified used, at least they used to be.
Even if they weren't, you really don't think used car values affect new car prices or lease terms?
BMW seems to do all right despite absurd depreciation and maintenance/repair costs on their used cars, but I think surely there is an extra cost to building cars that are appealing enough to convince customers to be irrational.