Good question. I often wonder the same thing. When I first got into crypto my mentor suggested that I when I purchase crypto in down market I only use 25% of what had to spend in order to save cash to buy more if it fell more. I asked him that same question because I was afraid of missing out of f it went back up. But he thought there was an equal chance of the price going up or down, but I would benefit more from being able to buy when it went down , then I would from buying all I could at one time. I don’t know if there are any studies showing him to be right or wrong. I think to a certain degree it’s style of trading and a preference to always have a little cash for great opportunities.