The easiest answer is that they shut down the rest of the miners to save money, or to sell them.  I imagine that some of that hash power belonged to customers, unless those customers have managed a refund or something.  Otherwise they probably could have used the spare hashes to provide RRP when it was originally due 3 months ago.

My payment today was 30% less than what I expected.  I assume that they would divvy up the block payment based on today's hash rates, not the average hash rate over the last 6 days, which would be more difficult to calculate.