"Both Bitcoin and Ethereum mining are very centralized, with the top four miners in Bitcoin and the top three miners in Ethereum controlling more than 50% of the hash rate.
The entire blockchain for both systems is determined by fewer than 20 mining entities."
In other words: decentralization in the crypto space is a myth, just as it is a myth that cryptos are currencies at all.
http://hackingdistributed.com/2018/01/15/decentralization-bitcoin-ethereum/
@Antanicus as bitcoin and wth ethereum gain popularity, so will the number of miners increase. of course all things start from centralization.
@Antanicus by the way, as i understand it, just because they mine the bitcoins it doesn't mean they act as a bank to YOUR bitcoins. They just process your bitcoin transactions and hold new bitcoins.