look at BTC miners with 1mb blocks and its only a few big ones with majority of hash power. Its the inevitable 80/20

Yea if you want to spend millions if not billions to 51% attack it and the public nature of bitcoin is such that everyone would know who attacked it leaving them legally liable then be my guest. There is more incentive not to attack it than there is to attack it. when will people realize this.

What sort of legal liability though? What law, regulation or contract would they be violating?