The idea behind using distributed compute nodes for blockchain was that the blockchain itself would carry applications with commercial value, and the token itself would represent a share in that commercial value which would scale accordingly. There would be no reason to mine coins if those applications never materialized, so effort would always track alongside the intrinsic value of the network itself.

Bitcoin never developed any real applications, and the entire value was speculation. This meant people raced to mine coins as fast as they could, well beyond the intrinsic value of the app stack (which doesn't exist). So now the network has effectively collapsed for all intents and purposes, but it is still needed for moving Bitcoin around, so the people who have huge investments already basically have to keep throwing money at mining in order to preserve the "liquidity" of their current stash.