Unfortunately discoverability and a saturated app store market is the norm everywhere. The video states that most developers there don't make any money, but that means Roblox also doesn't make any money, so I can't see how its exploitation.

If my kid was into creating games or art, I would encourage him. Kind of like running a lemonade stand, you're not going to get rich. You'll probably even lose money. A cynic would say you're enriching big sugar, but I think it's a good experience and something fun to do. Certainly better than being a consumer.