Would be insanely stupid to short a bullish asset class during a bull cycle 
I don't see it either. If BTC goes below $6K, I am selling my car and buying!
You better do it at $8,000 or $7,000. Leave the $6,000 to history.
But if ever that $6,000 will arrive, let it. We'll be having another round of buying party.
The most ambitious traders will aim at 3.5k
The most ambitious traders will therefore end up waiting forever.