Who says it has to be all in one place?
it most definitely shouldn't be all in one place... the fact that 30% were all in one place was what scared the pants off everyone involved.
this is true for the coins themselves but also equally true for the power to control the network. the more decentralized the better...
the devs have said that they will not roll back ever again.. but it does leave people wondering what is going to happen if this kind theft happens again or if someone puts a gun to their heads.
As a general rule, just about everyone around here has some skin in the game when it comes to Bitcoin. Since the sudden theft of 4 million Bitcoin would almost surely be a lethal blow to Bitcoin (and quite possibly to the very principles of cryptocurrency at the same time), I would love to see what song the people around here sing in the face of such an event.
I bet it would be vastly different for quite a few people in this thread.
if I recall correctly Mt Gox alone lost about 7% of all bitcoins to hacks.
so greater than 4% has already happened and bitcoin is not dead.
regardless of PoW or PoS... if a single entity had manged to steal 30% of bitcoins there's no doubt in my mind that it would have shaking bitcoin to the core also.
I'm not arguing that PoS is the problem only that PoS combined with small coin size encourages centralization and centralization is the problem.