I don't think all of the mined coins are dumped. Some people even hold on to them .
Miners have to pay electricity, and it is risky to hold btc in a bear market. The bull market could start in few weeks, but who can afford to wait?
If Bitcoin can't handle 10% inflation a year, it's not worth it.
I haven't heard a currency that can handle 10% inflation without some costs.
I pay my power bill in cash and keep my mined bitcoins.