and value would move between each "sector" blockchain using atomic swaps in wallets.
I like your thinking.
It would only work as we imagine if it evolved into this rather than being mandated to be so

I think we are somewhat already moving into this direction with some of the more serious alt coin projects out there with seemingly lofty ambitions, but still focusing on economic sectors.

One sector I think that I have not yet heard much about that is ripe for disruption is insurance
A peer to peer community insurance system would definitely attract attention. Slippery part is verifying fraud fairly.