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.