[Cr3aTor]

Mining in general have became a big problem in the blockhains. It takes a lot of power and to gather that power you need money, thus people will create mining centers. This way regular users have no chance to compete with these big boys. Besides that, it's also the problem of 51% attack in which you could control the ledger, thus the blockchain.

The bitcoin blockchain currently is in big trouble from my point of view, because there are already big centers of mining that have over 20-30% control over the blockchain. So they could easily associate with other big center and do the 51% attack. However this is pretty unlikely to happen.

As a solution, to this problem the most blockchains now want to rely on Proof Of Stacke(POS) rather than Proof Of Work(POC).