Yea, I know. It's open source. They can do what they want. Still sucks.
I don’t think it’s reasonable to expect an open source project to support everything
That makes no sense then. A power user may still want to run older OS versions for a reason. Take the training wheels off it and then it'll be a power user tool.
No doubt there are edge cases like that, but I don't fault a project for not catering to the < 1% of users who would fall into that bucket and would probably be the ones that cause trickier support cases. These would maybe also be the user that could just install it without homebrew then, it's not like homebrew is the only way to install software.
I get it - it’s a different beast with very different ideas behind it, but MacPorts is BSD-solid, and that’s a lot.
MacPorts has some level of support for PowerPC, but anything that isn't in the most recent ~3-4 releases is likely to be cut off from any number of packages at useful versions. (There's substantial work down to support Rust on much older versions of macOS, but there's also versions above which Rust has cut off older macOS versions.)
I believe that there's a recommended stream for when you need older versions support, but it's definitely a secondary target from what I've been reading on the MLs.
There's also https://github.com/dortania/OpenCore-Legacy-Patcher for the adventurous.
Also, the writing is on the wall: Ultimately, Homebrew will be ARM-only, once Apple's legacy support becomes ARM-only. At which point it's game-over for Intel Macs.
Homebrew solves the "availability of software" problem in the Mac ecosystem, but it does not solve the "Need to stay on the new hardware treadmill" problem.