You are missing the expression, which is the best time to buy was yesterday, and the second best time is today..
Yeah I thought of it too but I choose to write it that way because I believe yesterday is a past which can't be reversed so all chance given by yesterday are gone.
However, today offers a new chance for who are willing to take it and which might be better than tomorrow because no one can predict tomorrow, I had to cut out yesterday and replace it with today as today will later becomes a tomorrow
You are seeing it from the angle of motivational speakers instead of facing reality. The statement is not supposed to be difficult to understand neither does it mean you have to dwell in regrets for not buying yesterday. Rather it is simply saying that the more you delay buying Bitcoin, the less the opportunity of getting it at lower price is. Some people got Bitcoin when it was below $1k, some got it when it was below $10k, those are the people who bought yesterday which was the best time to buy. Now we have the chance of getting it below $100k, the second best time to buy so the question is are you buying now or waiting to buy at post $100k? It will surely get to that price in a matter of time so we have to use the opportunity we have now wisely.