All I said was that they use separate clusters to "isolate domains" which is a pretty vague description on purpose -- I did not intend to claim they do it for d

All I said was that they use separate clusters to "isolate domains" which is a pretty vague description on purpose -- I did not intend to claim they do it for different deployment environments as you've described. It's fairly subjective what types of isolation define "multi-tenancy" which is why there hasn't been progress made despite SIG and WG efforts in the past. While you do not believe network isolation should be included, there are plenty of developers working on OpenShift Online which may disagree. OSO lets anyone on the internet sign up for free and instantly be given their own namespace on a shared cluster full of untrusted actors.