Indeed. I've read not long ago a post that tells that best moment to buy bitcoin is "now" and was always "now", whether in 2009, 2010, 2011... and so on until, yeah, now.
People said its too late to buy BTC when it was 1$, they said this again and again when it went up to 10$, 100$ and 1000$. Even today when BTC is touching 70k, we are hearing same voices. Buying BTC at ATH is not a good idea, we must buy when its bearish.
As far as missing the opportunity is concerned, we are never in a position to predict what maximum price BTC will attain. So there is no absolute opportunity that is missed, its always open.