I don't think it's going to be a savior... the same things that make Android hard to modify can happen just as easily when GNU/Linux phones become popular.

How? Linux development is not steered by a monopolist acting to gain the maximal profit. It is distributed over many entities.

Well one way would be just like how Android phone manufacturers are doing it now... with locked bootloaders and binary blobs. Even current GNU/Linux phones still largely need blobs to work properly.

This is misleading. The blobs are only in the firmware, not in the OS, not in the bootloader, not running on the CPU.

Having a technical possibility to lock down GNU/Linux phones in principle in undefined future by undefined entity that doesn't even produce them yet is a FUD argument.

Not true, current GNU/Linux have OS-level blobs

PureOS running on my phone is endorsed by the FSF, i.e., has no blobs whatsoever: https://news.ycombinator.com/item?id=25504641

Why is there no Librem 6? Librem 5 is 7 years old, it's a low-end smartphone with a flagship price tag :(

Oh wait they released "Liberty Phone" - still low end(!), this time with absurdly high price.. You can get true linux phone 10x cheaper by buying something that supports PostmarketOS

Your post sounds like you're trying to spread FUD.

Librem says the Liberty phone is the same, it just costs more because it is assembled in the U.S. for people, companies, or governments that don't want it intercepted and modified by a bad actor.

This might justify the price of Liberty Phone, but doesn't invalidate my claim that these phones are low-end by todays standards.

Why no hardware upgrade after 7 years?

You can't easily find vendors supporting free drivers: https://puri.sm/posts/breaking-ground/

Also this: https://puri.sm/posts/the-danger-of-focusing-on-specs/