You're right that there are many kinds of interesting, but we mostly use that distinction to figure out what things aren't on topic. For example, celebrity gossip gratifies social curiosity (I say that without judgment—gossip is an essential human activity) but not on topic here.
HN gets plenty of opportunities to discuss universal topics like marriage/divorce, parenting, and so on. But because those topics are so generic and so emotional, as you say, they tend to slide quickly into the unsubstantive-sensational sort of discussion rather than the thoughtful-curious kind that we want.
We've learned over the years that discussion on such universal themes tends to be better when the initial submission has a lot of information in it, and also is alloyed with something unexpected rather than entirely generic. I don't think the current story has those qualities. In the first place, there's literally only one bit of information—already fully communicated by the title—so there's almost nothing to discuss; and in the second place, the story type is billionaire-blockbuster, which is about as sensational as these things get.
Previous comments on this point, if anyone cares:
https://news.ycombinator.com/item?id=8348372
https://news.ycombinator.com/item?id=23087737
There's also the old pg phrase "intensely but shallowly interesting", which I think probably describes this story, no?
The worst thing to post or upvote is something that's intensely but shallowly interesting: gossip about famous people, funny or cute pictures or videos, partisan political articles, etc. If you let that sort of thing onto a news site, it will push aside the deeply interesting stuff, which tends to be quieter.
https://news.ycombinator.com/newswelcome.html