If Mining BTC Even with free electricity cannot pay the mining equipment in a year, that will be the doomsday of BTC, 2000$-2500$ is the limit.
Use your head once in a while! When Bitcoin was in the bear market of 2016 with prices below 4000 miners were also below the point of profitability with no way to pay off equipment bought in 2014 for $600 and more. Did that destroy Bitcoin? Even if we repeat 2015 and 16 worst thing that can happen is another 6 months of bear market and maybe 4000 dollar low
Yes why people now think that because bitcoin price was falling, they conclude that it will going to be destroyed. If we will go back where the time were bitcoin was created, it is lower than its value today, but still there are miners already who gets profit from it. 2017 was just a big change when it pumped so high and changed the perspective of every bitcoin user because they are expecting now for a higher more value of it.