Here is another question, sparked by TPTB (and partially aimed at Iota, but not exclusively so):

* If there is no reward at all to performing POW (neither block reward nor transaction fees), what incentive is there for consensus to diverge vs converge?

One incentive for it to converge is the desire to have your transaction confirmed in a timely manner - this encourages transaction submitters to chose the chain with the most work and submit their transaction there.

Why would it diverge?