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.

A hub doesn’t increase decentralisation. It adds one node to the network as it’s one point of control to be ordered to stop providing the service. Decentralisation happens through dispersion of devices across the geography of the network. It’s why the internet was designed for geographical dispersion post a nuke.

Tradfi coder by day, hacker by night. Doesn’t know night from day. Freelance scribe. Dad cook. Dog butler.  Happy Grandpa. Draws badly.

Each Hub run by an independent entity, esp. if geographically distinct, increases decentralization.

Additional clients and additional Hub implementations would further increase decentralization.

There are many types of decentralisation. One is distribution of data for data resilience. Another is availability, and latency through adjacency. And in the crytpo world, another is jurisdiction dispersion.