There are lot's of people which are holding huge amounts of bitcoin and there are also lot's of big organizations or companies that are holding hug amounts of bitcoin!!! This set of people or organizations are the once called the Wales, they always have control over market they are the once that can pump and dump coins. They have the largest share in bitcoin which they are holding the largest parcentage of bitcoin. If people that are holding large percentage of bitcoin decide to sell off price of bitcoin will definitely crash and if people did not buy back I don't think Bitcoin price will be able to pump again!!! The main reason why bitcoin price is pumping is due to there are lot's of people investing in bitcoin there are lot's of organizations investing in bitcoin and still adopting bitcoin.
such scenario will not happen, imo. but on the theoretical side of things, of course, it will crash. in reality, it would take a lot of communication before this movement will happen. and i dont think thats an easy job to do.
as the use case of crypto is getting clearer these days, owed to pandemic crisis. i dont think these major holders will decide to sell their stash, now that many people are into crypto, bitcoin in particular.