Newly minted coins are all that's needed to crash the market. The BTC community needs to CONTINUALLY spend more then a million dollars a DAY to support the current price, they can not simple HODL the price up because thouse miners need to have their costs covered.
No. If miners stop unprofitable mining, difficulty will drop to compensate. In short, mining costs will always be covered because of this. Mining difficulty will adjust, meaning less will be spent on hardware and electricity. So the fiat-value of BTC will not need to cover miners.
The point is that the average profit margins are decreasing across the board, from difficulty increase to difficulty increase, thus a larger portion has to be sold than before to cover running costs. Eventually, the margins will be very tight, and it will be extremely competitive, so that pretty much the entirety of the 3600 daily BTC supply will have to be sold.
If this wasn't true, then the average hashrate growth in % would not be decreasing: