Fair point about aosp, although given Samsung's recent change to lock the bootloader (oneUI 8.0) and Google's moves against side loading, I'm not optimistic about other manufactures not following suit and locking the bootloader.

I think most people are not going to jump through the hoops of installing a custom ROM and the increase of interest in custom roms is and will be too negligible to most large manufacturers. To this point, supposedly, Samsung sold more locked bootloader phones than the previous unlocked phones (Galaxy S26 v S25).

I can see the lockdown as beneficial to the companies, if they are getting something out of it (like telemetry) that they can make more money off of.

To your Windows/Linux point, I believe that Windows activates a option (fast-boot?) that screws up Linux instillations. So, while they may not have locked it down, they do hinder it. Plus Windows would probably receive major backlash from the server folks/companies, if they tried to lock the motherboard previously (as, to my knowledge, the vast majority of servers are running Linux).

Yeah, I could definitely see a small manufacturer provide a limited stock, ready for custom roms.

I'm not very familiar with the space, but locked bootloaders seem to be very location and service specific (I read somewhere all of Canada is locked down).

I think we mostly agree too. I think I'm definitely the more pessimistic of the two of us. My thinking is there are still millions of people still on twitter, even after it became infested by Nazis. In my view, most people are tired and have limited time for their own pursuits. I don't think they will spend their time jumping through additional hoops, unless they absolutely have to.