I suspect one aspect of this is that the price at which you purchase a new motor is based on return of the “core” to rebuild it, similar to car battery purchase.
i think most Bosch owners here would want Bosch USA to have their motor in stock, and just for that reason would not put up a fuss about turning in the old motor to keep the supply going.
OTOH, the “must return” part does grate. We do have limited right to repair by purchasing a bearing kit from the UK supplier. At one time on this site, a Bosch bearing kit was announced via a Bosch YouTube. Never heard anything about its availability again.
It reminds me of “trade some freedom for security” arguments post-9/1. Clearly, dealers and most customers are fine with this process. But I think the OP’s original complaint is perfectly valid. I’m tired of leasing “devices” like my iPad, etc but everyone I know trades in their iPhone to get a discount on a new one. I don’t know a single person who wants to keep their old iPhone bc they own it. That the holdouts have few choices is bc most People don’t care (just complain a little bit at time of new purchase.)
edit: apparently the Bosch Service Kit does exist.