The wild thing is Second Life's 600K MAU players monetize better than Roblox's 350M MAU players -- both for the company (it's still not profitable despite huge revenue) and for the creator community:
https://nwn.blogs.com/nwn/2022/01/roblox-metaverse-revenue-s...
If anything I would look at VRChat for comparisons instead (a young demographic, especially on standalone headsets, and an ecosystem that's still very Wild West in many ways), though measuring numbers there would be much, much harder since most of the creator ecosystem happens outside of the app itself on Gumroad, Booth, etc (content subscriptions through VRChat itself are still only in beta).
I know a dozens of early teens (friends/classmates of my kid, kids of friends/colleagues ...etc) that are (still) playing Roblox.
I even know one of those older teens (friends kid) that is earning enough money from Roblox games - that it doesn't make sense for him to do a typical Dutch teenager job of stocking shelves in stores/markets.
From ages 6/7 and higher it's common for kids to say to each other "Don't need toy type of birthday present as I would prefer Roblox (or once they are a bit older Fortnite or other similar) gift card".
More than once our kid got so many that we had to "throttle" their "use" over weeks/months.
Anyway - yeah developers getting only 30% and Roblox keeping 70%, especially with all the fuss about the likes of Apple/Google/Unity getting into trouble for 70/30 split the other way - doesn't make sense.
Sure - there are bigger operational costs for Roblox actually running game servers (instead of just the store) - though not that much bigger, right?
Arguably not, because Roblox offers distribution. It's like selling on Amazon or Etsy — you give up an onerous-seeming cut to the platform, but people do it because a percentage of something is more than 100% of nothing.
Not much better but still a bit at 30,000 robux for $105 now
I know nothing about Roblox, but this YouTube short (from Pirate Software) came up for me recently, and made it seem like the revenue cut is a bit more nuanced: https://www.youtube.com/watch?v=mkihEtuVliU
His pinned comment also goes into a bunch of detail.
It's all designed to get a huge amount of free labor, while hiding how outside of a lucky few who benefit from the network effect, the average would-be game maker ("slum kid" or not) would be financially better off just using a standalone toolkit to make their own app and selling it on Itch or Gumroad.