This thread is oddly absent the key value of the huge mining network and that is bitcoin's ledger (blockchain) security and finality. That is what the huge mining hashrate gives you. Any sort of attack that tries to rewrite the blockchain has to contend with a mining network larger than any computing network on earth so its nearly impossible to attack. If half the miners disappeared tomorrow, yes the difficulty would adjust in a few weeks to become less difficult to find blocks and block time would get adjusted back to 10 minutes.

And then that day, the network would be half as hard to attack and take over the proverbial 51% and attack the ledger.

Seems to me bitcoin has clearly evolved to a long term store of value as the most important use case currently. That use case requires super high security that the blockchain and money supply stays safe and the giant and growing mining hashrate is the best thing to ensure that.