…They take 30% (wtf!)…
On 93% of the applications, Apple takes 0%. They vet your app for the users and handle distribution for $0.
They provide the development environment for free (Your developer identity costs you $100/year and is required to release software in the store, but the tools are free and you don't need an identity to use them for yourself.)
Of the remaining 7% of the applications, until you are pulling in $1,000,000/year from the Apple App Store the Apple takes 15% and pays the credit card processing costs out of that. (At the worst end for you, if you sell a $0.99 app or in-app-purchase, your credit card company is going to charge you maybe 12.4%, so you are right back in the same territory. My local deli won't even take a card for less than a $5 purchase.)
Now we come to the whales. Statistically about 0% of the apps, but they bring in the money. These guys are paying 30% and that is some serious coin. They are absolutely subsidizing the development tools and store mechanics. It must gaul them that they are the huge customer and are getting a negative discount.
I wonder how big a whale you have to be to go to a different store and take >70% of your users with you?
…have to examine all deploys (nevermind your emergency)…
People's milage varies here, and no one writes a blog post describing things working normally, but the store review process is so fast these days that I push my release candidate up, refill my "tea", ask the cat how her day is going, and TestFlight download my approved app to one of my untethered test devices to test. It's that fast. In the bad old days that process could have taken days for me, but now it's smooth. I've been releasing this app since there was an App Store and I've never had a release rejected, so maybe I get special treatment. And to be balanced, I know people in industries which have to educate the reviewer on the legality and compliance of their app on every release, so that part of the review process still could use some help. That isn't doing Apple or the app developer any good.
But… even though I agree with many of your points, I want all my apps to come through Apple, and I don't want to have to provide friends-and-family tech support to all my knuckleheads who will cargo cult install some unmonitored store and end up on the bad end of a bad person's scam.