To me, the point is that there are many complex challenges to building a real-time collaborative text editor -- so we are stuck with the feature sets of the few

To me, the point is that there are many complex challenges to building a real-time collaborative text editor -- so we are stuck with the feature sets of the few people who spent the time to tackle those challenges. Firebase eliminates much of the complexity, so that if you had a need for a collaborative text editor with one specific, niche feature, it may not be unreasonable to just sit down and build it yourself.