> I can very easily hop between different clusters running completely different apps/topologies and have a good sense of what's going on. A mish-mash of custom solutions re-inventing these wheels is, in my opinion, far more confusing

Kinda like jumping between Rails projects (assuming those rails projects don't diverge heavily from the "convention") vs jumping around between custom PHP scripts ;)

Or for Java Dev... kinda like jumping between Maven (again, assuming mostly follow the Maven convention) vs random Ant scripts to build your Java-based systems.

There will always be naysayers no matter what because they're used to the previous tech.