[danbruc]

Progressively harder mining means that the price of bitcoin must rise in pararell to cover the expenses of the miners securing the network.

I stopped following Bitcoin closely a decade ago, so I might be wrong, but I think the issue is the following. Mining was supposed to be eventually financed by transaction fees instead of the mining reward but the usage of Bitcoin for payments never really materialized. So there are not enough transactions to pay for the mining costs at reasonably low transaction costs. This also interacts with the low transaction limit of Bitcoin, even if people wanted to use Bitcoins for payments at large scale, there is no capacity for that. And the other way around, without the necessary capacity, transaction fees will be high, which will deter people from using Bitcoin for payments.