Just an interesting observation; Minecraft was sold for 2.5B $, let's assume Notch got 1.5B $ out of it. Buying that house alone cost him 5% of his entire wealth.
This is an investment. He didn't throw a $70 million party, he bought an asset he can sell in the future and which he presumably thinks will increase in value over time.
And anybody who just became a billionaire is not going to stick that money into a savings account, they will get hooked up with a very good financial advisor who will help them to grow their wealth. Say he has $1 billion, a decent but not great return on that would be 8% a year. That's $80 million! He could buy one of these every year, spend $5 million and still have $5 million left over. And that's exactly how he should and presumably will manage his wealth. You don't spend your wealth, you grow it and spend some of the income it produces. Which is precisely what any rookie financial advisor would teach him on day 1.
He could be broke in 10 minutes, if he turned all his money into $100 bills and burned them, or invested it all in some company that immediately went bankrupt.
But obviously he wouldn't do those things, because they would be stupid. And if he doesn't do stupid things, how is he going to be broke even in 10 years? If his current net wealth is $1B then he'd need to spend $100M every year even assuming zero investment gains. Again, it's not like spending $100M in a year is difficult if you are actively trying to go from being rich to being poor, but it's not the sort of thing that happens by accident.
In theory I agree with you in your sentiment, but I have a hard time truly imagining my life with that kind of money.