Epic is running a loss leader at this point so it's not an business model to point to, since it's subsidized by unreal and fortnite.
Microsoft on Xbox is taking a 30% cut so it wouldn't be farfetched to assume cut is more a strategy to try to expand market share and are willing to increase down the line if they got market share. And Microsoft is Microsoft so has lot of other profitable divisions to be able to run things at a loss.
One actually better to point to might be GOG which is also taking 30%, but in 2021 had a 1 million dollar loss.
https://www.pcgamer.com/gog-looks-like-its-in-a-much-healthier-spot-after-a-hairy-2021/
Which raises the question. What is actually sustainable? Especially the lower cut offered have other much more profitable divisions that are covering potential losses and not being the main source of revenue.