They could be playing the long view and realizing how much that address space is worth. If I were in charge of IT at those companies, I'd renumber out of the block and start thinking about selling the space, once it gets tight.

I've noticed that the perceived view in the netops community -- backed up by mailing list messages today, even -- is that such an IPv4 broker market is an inevitability no matter what the RIRs do. There are policies about it, but some regions (i.e., APNIC) have a model that encourages reselling space without their involvement.