Speculation has hardly been groundless. Apple had an exclusivity contract with AT&T for some time, it was obvious that they'd branch out to other carriers after they were free from that restriction, and Verizon is the most logical choice due to their coverage, infrastructure, and existing user base.

Granted, the breathless speculation without any shred of firm evidence about a Verizon iPhone on X date has been silly and annoying, but the fact that there would be a Verizon iPhone eventually has always been an incredibly logical step.