I would argue any amount we can get is still lightyears better than not being able to replace or inspect anything at all on the system.
I mean, kinda?
Is it really doing anyone in FLOSS any favors if the projects are legally open but not practically?
I feel rooked on Android tbh. If the idea was to give large companies a free way to manage the hardware resources in SKUs that are competitors to the iPhone, yeah, it definitely accomplished that, but that makes it only a means to an end. It's not like GNU/Linux where there's any ethos to seriously change how software and services are delivered.
Can you download, build, and install a basic Android system these days without touching a single piece of closed code? Absolutely. Will it be able to do much without closed binaries? No.
Android isn't GNU/Linux where there's a general ethos of making everything in userland FOSS if at all possible. Rather, it's a free OS that both Google and manufacturers can do anything they want with, including shove a ton of spy and bloatware on it, then make it to where you can't get rid of those things, at least not easily.
The optimism from 15 years ago surrounding FOSS in the mobile space is on its deathbed.