* Funny , how no one worries that only 4 BTC Mining Pools can dominate all of Bitcoin. *
Take us through a hypothetical attack scenario. What will miners who are pointing their hash power at these pools do, if the pool operators collude to 51% attack the network? Stay with those pools, or point their hash power elsewhere? Any rational miner will leave the pool.
Maybe the attacking pools could "steal" their users hash power for some hours. What would be gained? Some censored transactions, maybe a small rollback? I would be curious to see the incentives that would even justify pool operators doing that. They'd be nailing their own coffin shut.
* But with PoS it scares the hell out of them if 30 or more stakers could collude to dominate. * 
Between hardware, electricity and overhead costs, a sustained attack on Bitcoin requires billions of dollars.
None of these costs exist in a pure POS network. Existing stakeholders can simply collude together at no cost. This is a permanent condition. This isn't like mining pools in Bitcoin who can only temporarily leverage other peoples' hash power.
It is funny, in your mind, 4 pool operators would never 51% attack a coin,
because of the financial damage it would cause them.
But you think , Stakeholders would cause direct financial damage to themselves.
I suggest you reexamine your statements, because logically no one wants to harm their-selves financially,
but you think all stakeholders are on financial suicide watch, while all pool operators are not.
Look deeply so you can see how confused you are.
FYI:
You also don't understand staking verses mining,
miners only require 51% to dominate a network ,
stakers require closer to 90% to dominate a network.
FYI2:
You also missed the point that the Government can locate any warehouse of ASICS,
merely by having the power company report excessive energy usage,
where as no one can determine the location of a PoS client by it's energy usage alone.
Also a PoS Client could be running off of wireless laptop and moving between alternative locations on a daily basis,
something a warehouse full of ASICS could never do.