every single FAANG (and many middle tier companies too) distributes macbook pros to its devs.

Just because there is no viable enterprise-ish Linux computer that fits those environments. Sadly :(

Definitely not true since (at least at FB) you can also get an auxiliary laptop (Thinkpad) with Linux (Fedora). Just that no one wants them.

It really depends on the company. In my limited experience I can say that only FAANGs will probably allow such an environment. Other big corporations aren't quite there yet.

And yet that doesn’t constitute even close to the majority of developers.