Of course there are success stories as well, YMMV.
So, every year a fair number of companies 'exit', that is, their founders and their investors tend to make a substantial multiple of the value that they put in. The latest investors usually have the best terms, earlier investors have lesser terms and the founders will have the worst terms. The multiples for the latest investors will be the lowest, for the earlier investors higher and for the founders the multiples will be the highest. But that does not say much about the absolute 'take home' amounts.
It is rare - but not unheard of - for liquidation preferences to eat up all of the result, but it is not at all rare to see founders make substantially less than they thought they would make. And those are the good cases, in a bad case (for instance, a bankruptcy) all of the proceeds could go to an investor + all of the IP if you are not very careful. So make sure you understand the terms and internalize 100% that a large valuation during a funding round can work for you as well as against you quite easily depending on the final price your company will fetch at an exit and the exact parameters of the deal.
VC money is not free.
This is not simple stuff and plenty of founders are hopelessly naive when it comes to understanding their position.