ARIN/IANA/whatever should have had the stones to first put a large amount of pressure on the legacy class A holders and then take them to court. Declaring defeat before any action is taken is not a reasonable course of action.
Not naming names, but I recall one member of an institution of higher education stating at a meeting that from their (his?) perspective, they would give up their class A only if they calculated that the cost of defending against any potential lawsuit (which they expected they would win) would exceed the cost of renumbering (and they had done a back of the envelope calculation that it was in the millions to renumber). This is a clear profit and loss point of view. Why change voluntarily if there is no profit to be made? We can all talk about "the good of the community", but true altruism is rare (although we all want to see it in others).