Yes, it is possible that BTC could just disappear.
And the reasons are myriad. But all the reasons I know have signs, like many miners bailing. And I don't see any of those signs.
T.P.T.shouldn'tB may launch a false flag against bitcoin that seriously undermines its credibility, and sends it crashing, while regulations are piled upon it... and it will probably still come out on top.
But, I think it more likely that the signs in the window will say "Bitcoin accepted here" simply because it has name recognition. "Cryptos accepted here" just doesn't have the same meaning. And "Bitcoin accepted here" will be synonymous with most cryptos accepted here, like we talk about Kleenex®