if the approval rate is the only thing you're measuring, then I have to say the non-voting stake would mean they are not approving the current witnesses. as long as Steemit does not hold the absolute majority of supply, I see zero reason to do anything.
This is more and more becoming the EOS route, only a matter of time until cartels build. If Sun doesn't fork, that is.
Majority or minority of stake isn't a relevant point.
Can a single entity control the blockchain consensus? The answer is (was) a clear and present yes.
Should the blockchain witnesses have done something about this before? Yes, but the can was kicked down the road because the incentive structure for the owner of that stake and their promises were enough to not establish a consensus. The new owner does not have those incentives and did not make those promises. Furthermore they have communicated an intention to deprecate Steem.