You cannot blame people, so many people lose their money and many have wiped out their investment and there are investors who even take a loan to invest, this is the scenario that they don't want to be repeated, and they look for comparison, because it's a guaranty that they will make a profit, once they see that it's not going to repeat again.
Many people usually look for the patterns and bet a lot on the repetition, but as previously said, in 2017 the circumstances were totally different, I think that by 2017 there were the old whales, it was not in the Paypal market, nor Elon Musk , much less Microestrategy, in addition to 2017 living conditions were different, there was no pandemic.
In 2021 it is very difficult to be guided by repetitive patterns, I do not know how much some analysts focused on chart patterns have been able to succeed, but I think they have not been successful, if they normally have a low percentage of success, now with these circumstances it will be more difficult for them.
This year at least where I live, the pandemic has become radicalized with new strains, this has caused much of the world to go back into confinement, although there are several vaccines, the virus continues to rage, and this may cause some panic in the investors. When comparing Bitcoin to gold, there was some short-term correlation, but now it has moved far away from the similar behavior that both charts had, many who are gold investors assume that gold can or will go bullish based on this positive correlation.
I don't know if you remember that many famous people like JP Morgan came out saying that Bitcoin was going down and a series of bad news, and now in 2021 JP Morgan advises not to wait for big corporations to buy Bitcoin for others to buy.