The 3 makefiles I wrote were actually for a medium-size open source project https://www.oilshell.org/ (medium measured by lines of code)

I could probably write a blog post about this, but for two of the Makefiles I needed to enumerate the rules dynamically (inputs weren't fixed, they were "globbed"). And my memory is that this interacted very poorly with other GNU make features build variants

Whereas that pattern is extremely simple with Python/Ninja. Just write a loop or a nested loop and generate a build rule on each iteration. It's done in 5 minutes, whereas GNU make was a constant struggle.