That's correct, but we can still boycott companies that do this.
There is no choice outside Google/Apple when it comes to mobile devices. None which are fully compatible with a normal person's way of life, or which provides access to the same apps.
It may be technically possible to avoid them, but 'technically possible' and 'competitive alternative' are worlds apart.
That doesn't help if everyone you want to interact with refuses to talk to you if you don't have an iPhone because doing that has become fashionable.