The fact that you have to waste ever-escalating amounts of electricity to make bitcoins doesn't ensure that it's decentralized.

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.