Someone wants to make an easy profit off the coat-tails of Apple's success
Why can't complementary products exist? You wouldn't consider a train timetable app parasitic. In fact, my local train network encourages such apps so that they don't have to do it themselves. Businesses can build co-operating products.
In fact, when the Pebble first came out its notification handling was better on iOS than Android because Apple specifically made it easy. Pebble, Fitbit, and Garmin paved the way for smart-watches. Once the hard work was done, then Apple produced their own. And what a coincidence, everything gets locked down for third-party watches.
Nobody is complaining that they don't make things easy. They're complaining that they make it impossible because they compete with Apple.
If one or more companies has the ability to lower the price of a good or service, that's good for consumers.
If one or more companies has the ability to raise the price of a good or service, that's bad for consumers.
The complaint here is that Valve, Apple, and Google have used their position to increase the cost to consumers while reducing the profitability of game makers.
I'd be less concerned about bad actors being able to install the software. I would assume that the phones would still verify the installed packages.
But this probably means that if you are concerned about some threat, you can't just assume that a switched-off phone is safe.
Apple was spending $30 million per month on infrastructure in March 2019. (That's for everything, not just their app store.)
Let's assume that those costs have remained flat from 2008 to now. (That's going to be too low for later figures, but much too high for earlier figures. So it's more likely our estimate will be too high.) Over that time, Apple would have spent $5.4 billion on infrastructure.
That $5.4 billion doesn't account for all their costs, however. Backblaze, who provide cloud storage only, claim that infrastructure costs make up 40% of their total costs. Apple is larger, and thus it seems reasonable to assume they spend more. But at the same time, some costs don't go up with scale. In any case, it's the only figure I have, so let's use it. That would make their total costs since 2008 to be $13.5 billion.
As calculated elsewhere, depending on the breakdown of 15% and 30% cut taken, Apple's income just from app store fees is somewhere between $56.4 billion and $137.1 billion. If this was their only income relevant to the costs (which it isn't), and assuming our calculated costs are correct (unlikely), that means they're making a profit of between 76-90%. That's an exceptionally large net margin. Compare that to industry averages, where the highest net margins are regional banks at 30%, and the various technology industries are all between 14-21%. Those are averages, of course. Individual companies will be higher or lower than those numbers.
Of course, there's a lot of (unavoidable) fudging in these numbers. But it's unlikely that Apple will release the actual numbers. It's in their interests to keep everybody guessing.
I anticipate that Apple will find some loophole to undercut the whole thing.
Like, for your app to be installed through a third-party appstore, it still has to be checked and signed by Apple, and they'll charge $1000 for that. Double if your app takes payment.
"The robot has trouble finding the barcode. So we'll take pictures from various angles as it moves down the line..."
"Yeah, that'll make sure the barcode is seen."
"No... we're going to give the pictures to an AI to figure out what the product is."
All the simple programs have been written.