Speculators can earn on falling asset as much as on growing, unlike investors that have only faith remaining (if ever) in such a case. Don't have illusions on this account. All speculators need is volatility...
Easier said than done. Almost everyone who have ever tried to short bitcoin were wiped out since they can never predict how high the market will go before a crash
Simple question, how do you know?
The time that market crashed is a very small part of the total bitcoin price history, means majority of the time the shorters were squeezed, unless they can call the top, but a top is only identified after a crash