I can expand: They are not actually better at capital allocation than the sum of market participants (obviously, who is?) and so when they lose money it is because the market is so stupid they are losing money, rather than some failure in their ability to model.
“Market can stay stupid longer than you can stay solvent.” that is an argument for not shorting. But you can still abstain from investing, which will be sufficient to outperform those who did invest if you are right.
No one is claiming to be about you time anything which is what’s needed to actually accomplish what you’re asking for. However, if someone says “if you drive at 200 mph at night with your lights off on a winding road in the rain you’ll crash”, you’d be asking “yeah sure, but you can’t tell me which mile marker”.