A real bad thing here is the asymmetry. To prevent 51%, the network has to burn enormous amounts of energy 24x7 forever while the attacker only needs his energy for the duration of the attack.
Counterpoint: physical security largely works this way too.
Well, things work much better in crypto (not proof-of-work, but the "real" one).
And now a single company can. Progress!
It has always been the case that a single company could 51%-attack the network. No regression here. In fact the cost has continually increased over time. So, yes, progress.