If you look back in time, absolutely all the people who bought any cryptocurrency 5-7-9 years ago now have huge profits! And it's not necessarily buying bitcoin! That's why I am sure that HOLD is the best strategy!

A good strategy but I doubt it is the best. The best way in my opinion is to "buy low, sell high" because in such way, profit will be earned at a faster rate and also, the market price is not consistently increasing as years are passing by. For a long run it is, but consider how many years will be needed in order to generate a profit which could be earned for a year only if you'll do 'active investment'.
Going back, whether to stay or not, it does depend to the user. If he feels bitcoin and crypto investments are risky, the one is free to go. No investment will give assurance on the profit and I think it is also applicable in this technology.