Naturally, people have held their Bitcoin because they believe it will become more valuable in the future. Their idea was great and I support their thinking but I suggest them not to expect too much. Maybe 10 years from we can see Bitcoin reaches $500k and if that really happens, these holders will surely get happy while those weak hands regret it.
Well, I'm too positive as well that Bitcoin adoption went so strong, and to see people will use this as a currency.
IMHO, it's okay to expect much if it's for bitcoin. But for the other coins, it's better be applied to be neutral or give not too much expectation. That's just what I think since bitcoin is likely holding the whole market and it moves all of them every time it goes up or down.
$500k is a too much expectation and I'd love to hold bitcoin even only one until that time comes. As I've said that it's okay to expect that much, your expectation of it being as a currency isn't that much because it is actually a currency already or maybe it's about being used and replaced fiat.
As for my experience, it is better if you do have your own prediction and keep it to yourself and see if bitcoin can reach that price or not. Or just stick with the basic, continue to hold and accumulate because the chance of bitcoin having a massive growth in the coming year is high. So no expectation, just time will tell. A for the other coins, there could be some solid coins, but not like bitcoin though. There are some solid altcoins that can give us good profits in the future as well, but majority of us sticks to bitcoin.