That's what my math came out to.That would be implying that nearly 2/3rds of the commissions they take is needed for break-even. You really think it costs Apple $14.75 BILLION PER YEAR to run the App Store? Because that's what 67% of their commissions would come out to.

Minnesota and Arizona Bills Aim to Let Developers Skirt Apple's In-App Purchase Rules
Here's my thinking. App Store profits is derived from two areas. The cost of running the App Store (which doesn't change, because the number of developers is assumed to be fairly constant), and the revenue from games and IAPs (which is variable in nature). We also know that about 85% of...
Apple's App Store revenue was estimated to be about $64 billion in 2020. This is close enough to Neil Cybart's own estimates, so we will roll with that. He also estimates that the App Store has around 40% gross margins. This is because Apple has margins of about 65% for services. This includes the money from Google (which is basically pure profit), and more lucrative ones like iCloud and AppleCare. So App Store margins would be lower to balance out.
I admit I also don't know just what the costs involved in running the App Store are, but it's definitely not the 80% the experts are suggesting. It's possible that there are other costs associated with the App Store, like new software tools and APIs, which get charged there as well.So you can see that if Apple were to reduce their App Store cut to 15%, my estimates show that the App Store would effectively be run at a loss, which in turn means that Apple would be effectively subsidising it using profits from elsewhere. To break even, we take (12/64*100%) which gives us 18.75%.
Granted, I am no financial expert myself, but something about all these fanciful numbers being tossed around just feel off to me.