To be fair (as a Samsung Android and MacBook user), so do nearly all phones altogether. On a computer, you can just install Linux to have a Microsoft/Google/Apple-free OS. But nearly all smartphones run Android (if not iOS).
I guess then that we need more Linux phone development.
Yes and no. You need an unlocked or unlockable bootloader, which is becoming more and more difficult to find. So you’ll need speciality manufacturers, or ones with that feature. For example, in the US, Samsung has had locked bootloaders on all its phones since the Galaxy S7.
Obviously your point is correct (e.g. I have an older, but usable OnePlus 6 with an unlocked bootloader). You just need to be more deliberate when choosing a phone and keeping all of this in mind.