"World's (almost) richest person consistently sets prices using 420 and 69 because weed and sex are funny" is just so dumb.
The 420 joke is a reference to his tweets trying to take Tesla private. 42 wasn’t in the right range as a target price. But 420 was. And since this tweet turned out a debacle, he now uses that number. It’s like 42 squared. Or rather, an order of magnitude better than 42.
If you don’t get the joke and rather want to believe he has some weird connection to the weed subculture, feel free.