Note that it's not that much, since I only invest like 5-10% of my portfolio in a position, which was not that big a year ago, but it's getting sizeable.
However if somebody would have dived all in, and took massive risks, like if somebody has 10,000$ gambling money that they are not afraid to lose, then that money would have already made them 13,553,496.52 $.
Crazy.
Do you think this is sustainable over time? Could it be repeated?
Depends how well altcoins coins are performing, I don't think these ROI's are repeatable, but I think the altcoin market still has a lot of juice in it, maybe like a 500x multiplier if you were to buy some good low market cap coins.
That is like for the next 6-10 months I believe. Of course in the future there will alway be some altcoin that makes 10,000% gain. There is a wave of innovation coming, and we simply just cant let this train pass us.