"Homebrew's insistence on leaving OSes behind that they deem to be "too old" is becoming a problem as the years click by"

Indeed! I have a VERY usable Macbook Pro from 2015. Even with the newest version supported macOS version (11) Big Sur (which is still quite modern) it doesn't have any binaries for apps, which means it has to compile every single app and dependency.

I managed to update to macOS 14 (with the help of OpenCore Legacy Patcher).

But this just buys me one year to use Homebrew. Next year they will retire macOS 14.

And my machine is still very usable, but it will become junk from a developer perspective unless I have homebrew (or something similar).

It annoys me because I think this problem is fixable. Either community repos or more donations to homebrew to compile apps for older macs.