Assume it was 1-click and 100% automated to deploy, run and update a Hub.

How much per month would you be willing to pay to run one? 

No direct economic incentive other than you know you're supporting Farcaster decentralization and you have your own copy of the network.

OK, if you're answer is you wouldn't run one.

Working on Farcaster and Warpcast. Longer thoughts at https://dwr.email

Depends. If there is a credible alternative to the MM-run hub, either bc:
1. A non Warpcast client succeeds , or
2. People start using Warpcast to follow other hubs
…then if do it for $50 a month to help censorship resistance.

If in practice a non-MM-approved cast appears nowhere, I wouldn’t run my own hub.