Noto doesn't ship with OS, and users need multiple fonts for different use cases.

Grandparent comment is saying that Microsoft, Google, Apple could settle on a common set of open licence fonts and bundle them with the OS (and Linux distros / other OSS OSes could also do the same). Then web design & dev could rely on those fonts without having to locally serve them, or embed with Google fonts, etc. Noto could indeed be one of the bundled fonts in this alternate reality.

But no real incentive for any of those big players to do so, and disincentive for Google who gain surveillance data from font embeds as noted elsewhere in thread.

Although if you're not too picky about the finer details or being perfectly consistent across every platform, the system fonts are generally good enough nowadays to put together a pretty decent stack without having to resort to serving web fonts.

https://github.com/system-fonts/modern-font-stacks

Even if you are using web fonts, those stacks make for good fallbacks.

Apple ships six Noto fonts (non-Latin alphabets) with the current version of MacOS.

first of, currently it is impossible to cover all of unicode because, surprise surprise, we still have page table issues!

the same char in zh, tw, jp, kr might use the same unicode id but have different glyphs.

secondly, yes, but even google fonts strip most things from noto it serves because they want the fine grain data of each site/user is using wink wink.