WHEN exactly will Bitcoin fail

My wife and I got together in 2011, married in 2015. We have two kids, soon celebrating our ten year anniversary, still going strong.

A friend of hers made a prediction after meeting me less than a month into our relationship, i.e. back in 2011: I'm not the right person for her, and the relationship will crash and burn, and she will leave me.

When recently asked how the friend feels, she says she stands by her prediction, it just hasn't happened yet.

I'm curious - let's say r-Buttcoin turns out to be "right" and Bitcoin crashes to zero and everyone who was scammed loses all their funds... in the year 2200. Does this really count?

My question is, what's a more testable prediction? By when should Bitcoin have failed, for r-Buttcoin to be able to say "we were right, you were wrong"? A year? Five years? Ten years? Fifty?

(I've asked my wife's friend the same question about her prediction, but she's still thinking about it)