>I think performance is really the best differentiator.

I don't understand this at all. Most open source projects start out equally as a means to give back to and collaborate with the community as well as showcase one's skills. You're asking me to purposefully publish badly optimized software? I don't have it in me. That offends my sensibilities of craftsmanship. A 'slow' open source project will never get traction. Even if it did, I also don't know how an open source project wouldn't immediately have it's obvious performance bottlenecks fixed.

Far better to go the VSCode route. Release a useful project, then release paid extensions for it.

this is the open core model, it works well for things like GitLab (as far as I know)

and in effect GitLab is doing a BSL-like thing by after a few years they release features to the free tier

but it rarely works if you need to decline contribution from people who would eat into your profit margins. I think ElasticSearch had this problem (and the community basically ended up with a few forks, because people sent the patches for security features that were in the enterprise version, and to no one's surprise they did not get merged ...)

so, I guess it works if there's a huuuge scope with plenty of things to contribute, to shoot for the moon together, without hurting the business side too much.

It ain't performance, it's cost (which increased performance can improve, but it's far from the only factor).