Good idea, thanks for raising this!
The split used to make more sense because we didn't have frequently-tagged builds, mostly because we didn't have great testing (so we had a lengthy manual test process before merging to master). Today though we have good testing (could still be better though) and a process for easily tagging builds, and we've had around one a week recently without major issue. So I think we can do this now.
Tasks for doing so may include at least:
* Change the default branch on github, trivial.
* Update emsdk, probably easy (just the code for building from source, as getting binaries doesn't refer to a branch).
* Update releases CI (auto rollers etc.). I'm not sure how that works.
- Alon