Bear market always start when people want to go all-in, on a particular asset, that seems going to infinity.
Since 2008, the story is always BTC going to infinity and people put all their money trying to do that.
Then the next year, they say its going to 0 and put all the money trying to do that.
Its the same story right now, but since 20k, the big bank had open their crypto trading desk :)
Trade at you own risk!