Bitcointalk has never again seen real overnight millionaires as it has with Nxt. They were at the right place at the right time.
Frankly, a lot of money in hands that aren't used to savings is a dangerous affair.
How many of the Nxt millionaires still have money left?
I have seen several similar to situations. Its not necessarily known to the people at the time that will get rich, in part by randomness. Say you were a Nxt investor and put in 100$. Now you have 100'000$ and sell. Then the amount goes to 1M$. Not selling early is hard. Or the same people will squander their new sudden wealth with new adventures. it is interesting to observe this new wealth distribution mechanism at work. The more interesting opportunities are structural and thoughtful investment, not ICO lotteries.
Honestly, if people are going for investing in opportunities that are 'interesting', 'structural', and 'thoughtful', they wouldn't be investing in altcoins in the first place. The ONLY reason people invest in altcoins is for profit. If someone seriously believes in cryptocurrency appliances to the real world they would be investing in Bitcoin start ups. It's as simple as that.