Problem is, we live in the present. We cannot invest today's paycheck 3 years ago, we can only decide to invest it now or to wait for some time in the future.

I remember a poster who said that AAPL at 105 was too high and he was waiting until it got to 100 -- which he said it absolutely would -- and THEN he'd buy it. That was before the 4-1 split, so he was waiting for split-adjusted 25. AAPL never hit that and now is 220. And AFAIK he it *still* waiting. But he stopped posting, so who knows.

"actionable" means "strategy that can feasibly be accomplished shortly." or "ready to go or be put into action."

From that standpoint, CAPE is not actionable.

Just not actionable in the sense of telling you whether the market is going to go up or down next.

Yup. But that's exactly the information that we want to know. So all high CAPE tells us is that the expected future returns for the next many years will probably be lower than average. It doesn't tell us what to do, just what to expect.