In a blockchain type of consensus sytem:
1) you cannot guarantee that a single entity won't somehow obtain more than 50% of the active resources used to create blocks, whatever they are.
Technically, you can with ease in the
short term by boot strapping a DPOS system with 101 pseudo-random, pre-selected candidates from various countries, then treating their role as a supreme court judge type position where it's difficult to remove them. The challenge in that scenario is selecting what method for allowing their replacement: voting with money from coin holders (plutocracy), other delegates (democracy), or thousands of other combinations of variables.
The method BitsharesX used for their system was executed extremely poorly, and I've already come out against their system, so don't even think I'm shilling for that. Some people will say 101 delegates isn't decentralized, but when only 1-4 mining pools really matter in Bitcoin, it beats the hell out of that decentralization, or lack thereof.
There are many other technicalities to hammer out as well, such as should delegates be allowed to run anonymously, or force it so the original 101 delegate names are handed down over time for people to better keep track of. Then you have things like TOR/I2P integration and timing attacks and all that.
Look, that is just externalizing the problem.
I'm all with you on better types and methods of democracy and I feel that the current political system is rotten to the core.
I would also warmly welcome any incentives that foster stronger decentralization of bitcoin mining.
Nevertheless I stand by my argument that from a technical standpoint PoW and even the current hashrate distribution is not as problematic for bitcoin as suggested.
Like you hinted governments can and probably will try to manipulate cryptocurrencies until they are a shadowy joke of what they were and are intended to be.
But it will happen in the public space and not through a brute force attack on hashing power.
Through lobbying, through enforcing stupid regulations and maybe even through making the software illegal or otherwise manipulating it.