The most HOLY concept of bitcoin is that of HODL, its what the pure of heart do they "Hold on for Dear Life", forever until 'economic ruin', Now the most silly fact of Bitcoin and HODL is that OWNER of BITCOIN, .e.g. BITMAIN they have sold most of the coin ever mined back to the flock, the suckers; It's like animal-farm, where 4-legs good, 2-legs bad; In bitcoin its ok for BITMAIN to sell, but its NOT ok for the flock to sell. Go figure how stupid can people be? Well like George Carlin say's take the stupidest person you ever met, and divide his IQ by 2, and your close to the average 'stupid' of society.
it's common sense to assume miners will sell---at least to cover costs, if not more. miners have operational costs that investors don't need to deal with. that's why the idea of HODLing emerged among investors, not miners.
bitmain also doesn't sell everything by any means:
At the end of June, Bitmain held $886.9 million worth of bitcoin, bitcoin cash, ether, litecoin, dash and other crypto assets more than twice what it held in fiat currency.