people seem to forget the fact that when someone cashes out big profit from meme coin there's people losing buying at peak, its not really profitable for many people but they don't tell anyone about their losses, at least with some coin with real product you got product that can be utilized but many meme coin trend are short lived.
in this case like as you mentioned even meme coin fall under category of altcoin and meme coins and other altcoin generally are just as volatile depends on the coin we are talking about here.
if its stablecoin indeed there's some case where the stablecoin are being volatile, i still remember when usdt and usdc has some value decrease, usually most of the stablecoin that depegs are made algorithmic stablecoin where they didn't really peg their coin to usd but to other coin to keep value.
There is no such thing on this world as a free lunch, if someone earned 100x their initial capital, then in aggregate there are traders that lost an amount even bigger than that, as we must remember that exchanges also charge fees for each trade you do.
This means that for every success story we read on social media, there are dozens of stories that are not shared of people that lost everything, and they suffered those losses just because they were pursuing an impossible goal as they thought this was the right way for them to make a lot of money.