That's a ridiculous misunderstanding of value. Just because you waste valuable resources to produce something doesn't mean the thing you produce is now valuable. If I feed my dog millions of dollars worth of beluga caviar, it doesn't mean his dogshit is now worth millions.
To the degree that bitcoin is valuable today, it's because speculators think somebody else will pay them more for it in the future.
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.
To the degree that bitcoin is valuable today, it's because speculators think somebody else will pay them more for it in the future.