The problem isn't how it's handled or how incremental it is, it's that there are so many upgrades with breaking changes, at least that's what they're communicating to me with their version numbers. There's also the lack of any real LTS versions I mentioned, 18 months doesn't cut it.
> They are much more incremental and even the two times the entire renderer has been re-written
Telling me that they've rewritten major components that frequently isn't exactly convincing me of the stability, its validates my previous belief that it isn't stable enough.
When they've got versions that are supported for 5+ years post release I'd consider it stable. It doesn't matter how good your upgrade guide is when you run into a bug or limitation with the current version and realize that you have to upgrade the entire framework and deal with all the breaking changes to get around it.
Compare that to react where you've got at least 3 years (assuming they follow semver) between breaking changes.