To the degree that bitcoin is valuable today, it's because speculators think somebody else will pay them more for it in the future.
True decentralization at this level is why it is valuable
If anything, it means that economies of scale will favor larger organizations. In fact, that's what we see, with a few large Chinese mining syndicates controlling a majority of the hashrate: https://www.buybitcoinworldwide.com/mining/china/
Compare bitcoin to a real decentralized system like bittorrent, or hell, email.