> According to Forbes, Son's estimated net worth is US$30 billion, making him the second richest man in Japan,[1] despite having the distinction of losing the most money in history (approximately $70bn during the dot com crash of 2000).[3]
And that's by law: https://en.wikipedia.org/wiki/Gresham%27s_law
In an environment dominated by information asymmetry, the "bad investments" drive out the good ones. When we say, "dumb money," we're describing information asymmetry. The dumb money isn't as knowledgeable about the value of investments as the so-called "smart money."
But the net effect of a market being dominated by dumb money is that good investments either vanish, or get turned into bad investments to compete with the other bad investments for money.
SoftBank has been chasing all kinds of bets over the last years, some of which make even r/wsb sound wise in comparison.
That's the problem when there is way too much "dumb money" floating around to be invested for even the most minuscule returns - it will inevitably flow towards high-interest, high-risk stuff. And SoftBank in particular was propped up by a lot of Saudi-Arabian oil money (or, given their dismembering of Khashoggi, I prefer blood money).