I refuse to believe there are people who use Gentoo seriously. There is no possible way it’s not just a joke about how goofy a true stallman-esque approach to FOSS is.
The proprietary video drivers for ARM SoCs have definitely been a problem for years and we can’t rely on third party alternatives or first party support from linux popularity.
As far as software supporting arm, there are translation layers that can run x86 binaries on it and I am confident with more development and more powerful chipsets that won’t be much of an issue for most applications.