I often fantasize, if I knew Bitcoin since 2010, surely I'm a billionaire right now. I'm sure many also fantasize like me.

You are not alone man I also do the same thing and think that if I found it back then,
But I think even if I knew Bitcoin back then I wouldn't still have some savings till this day unless I really am earning huge amount of crypto back then that I could just hold some of them while spending or buying things that I want.