This is exactly what I did. I even participated in the Yarn project a bit before it was fully open, but as npm 6 and 7 brought major speed improvements, workspaces, and overrides, I don't see the need for an alternate package manager anymore. As a library maintainer using the same package manager that most of my users do is a pretty big help.

I'll be very happy when npm's linked install strategy is stable so that there's less reason to use pnpm and we get dependency isolation in monorepos.