If there’s some new hypothesis it’s likely to be proven or disproven quickly. If you look at an old one, like the Riemann hypothesis, that people have tried and failed to prove or disprove, it probabily won’t be proven or disproven any time soon. Thus, it’s not hard to find something more likely to be proven quickly than the Riemann hypothesis, but is still less likely to be true.
If there’s some new hypothesis it’s likely to be proven or disproven quickly. If you look at an old one, like the Riemann hypothesis, that people have tried and failed to prove or disprove, it probabily won’t be proven or disproven any time soon. Thus, it’s not hard to find something more likely to be proven quickly than the Riemann hypothesis, but is still less likely to be true.