But what would happen if the oldest and most valuable asset on the market, Bitcoin, dropped to zero?
Such thing would happen only if an unrecoverable and very big problem would be find in Bitcoin. Until now no such thing has happened (the big problems were early and recoverable), so we can say it has already passed the test of time and 0-value scenario is pretty much unlikely.
However, was this a genuine question or just some attempt to advertise a website?