It still won't solve the "Qualcomm won't update the BSP" issue, though.

This right here!

Closed SOC BSPs that are tied to android are the real problem! If google had stuck with the standard Linux APIs or added appropriate new one when they needed them and where more strict about open software we wouldn't be in this mess.

Not true. Witness the routers or another embedded devices, that are using standard Linux and yet are never updated.

Or worse, coming with obsolete kernel right at the release day.

What is this issue?

Good idea. It fits now more than ever. I have said this before. Right now SoC's are passed the threshold performance wise. For e.g if you are not into playing high end games your phone cpu is enough for 5 year if you only doing web browsing watching movies and reading mails.

The take rate on paid software updates probably wouldn't be good enough for that to be a realistic option.