What you mentioned is a good and real assumption when viewed from history. However, my view is just general - there are always investment opportunities in the money market world and there are no time and event limits if you really want to enter the market and start an investment journey, of course not carelessly. because capital and time and mind are at stake here. So when are good times to buy? the answer is the best time to buy really depends on each individual's personal goals, risk tolerance, and the investment strategy that he will use later.
If we that missed Bitcoin in 2009 had the power to go back in time then I believe we would all have gone back to 2009 and definitely invest in Bitcoin we a good amount of money we have, but in reality that's not the case, we can turn back the hands of time neither can we keep regretting missing Bitcoin at that time, the next best time is starting now, although the profits of those who bought Bitcoin back then and still holding up till now would be more regardless of that we would still make good profit in the long run if your reason for joining crypto-currency is mainly for investment purposes.
I don't think there is a better time to invest rather it's best to know
#What you want to buy
#amount of Capital you have
#your time frame for the investment
These are amongst factors you should consider more when trying to invest in crypto-currency especially what you want to buy, If I was asked I would always go for Bitcoin.