Ultimately, proof-of-work is actually a proof of faith. How much resources are you ready to waste in order to prove your faith, and have a chance at discovering the next block?
Now, a (globally enforced) tax would raise the bar for every miner. The same amount of resources would be wasted by the miners: their resources and faith remain unchanged. But now, a portion of the miner waste would go into community resources. A 99% tax would be great!
The only problem is enforcement; if someone doesn't pay their taxes, they have a much greater proof.
Maybe it can be enforced by the blockchain? Lets say a blockchain recognizes a "government" entity -with a magic address-; a consensus rule could be that 99% of the reward goes to it?
