To expand on this point, if Fukushima were Chernobyl and Japan the USSR, the Sarcophagus would have been completed on October 27th, of 2011. Two years ago.
(By no means is that structure a fine piece of engineering, but considering the constraints I find it hard to fault them for that.)
In effect, Fukushima already had a sarcophagus integrated into the structure of the building in 1971, 6 years before Chernobyl even started running.
I don't mean to suggest that Japan should build a sarcophagus; I only mean to give an idea of the sort of timescale for significant engineering tasks that the Soviets were working with. They slammed it into high gear pretty rapidly.
So while I think that Tepco did make horrible mistakes, I am actually not sure that the response was less than optimal. Largely because the USSR did commit similar mistakes in Chernobyl, for example not registering the liquidators.