I think we all have faced this situation like you. We missed many chances to become rich. We miss the correct time to buy or sell multiple times. When the ETH price was about 10$ in 2017 I bought couple of ETH and sold at $100. But ETH hit $1000 in 2017 so If I could hold for a year, I may become rich at that time. So, I know traders have lots of stories like this which regret them. But this is not the end we can get more chances in future to use wisely.
The only opportunity that I still regret till date that I never took was that of bitcoin, because that is a mistake that can never be corrected again, even to $1000, it would be impossible for bitcoin to ever go down that low again, but you see all these altcoins that you are saying, I still don’t see it as a missing opportunity because if you look at some of them now if not majority, they are almost down and lower than the ICO price itself.
There is this believe that we will still have altcoins season which they all have the tendency of having that multiplication they had in the past, so if we still invest in the genuine ones now, it would be an opportunity for the future, but right now, I think the lowest you can get of bitcoin price right now is even $7000, so it can never be like when you bought bitcoin at 0.001 usd.