In finance we say "past performance does not guarantee future returns." Not because we don't believe that, statistically, returns will continue to grow at x rate, but because there is a chance that they won't. The reality bias is actually in favour of these getting better faster, but there is a chance they do not.
this is true because markets are generally efficient. It's very hard to find predictive signals. That is a completely different space than what we're talking about here. Performance is incredibly predictable through scaling laws that continue to hold even at the largest scales we've built