The listed amount is actually an annuity that pays out over like 25 years. The base lump-sum amount is usually only around half of the listed amount. So a $2b win would only pay out about $1b in cash. And then that cash amount is heavily taxed.
You should almost always choose the cash option even if the annuity is a “larger” total, because the annuity’s rates very rarely beat inflation rates over the 25 year time period… So you’re better off just taking the cash as a lump sum and investing it in index funds and bonds, which will virtually always beat inflation rates over time.
But all of this is to say, it’s not quite an 80% tax rate. It’s more like 55%, once you consider the fact that the cash option is already only about half of the listed winnings.
Which is really only used in the americas. Europe/Asia doesn’t use it, except in specific circumstances where the child wouldn’t be eligible for citizenship elsewhere. But even that is only due to treaties set up to prevent stateless people. If the child would have citizenship elsewhere (like in America), the European/asian country would tell them to apply there instead.