Spotify already pays the enterprise fee. Does Spotify's music library run on Apple's servers or infrastructure?
Do the two have to be mutually exclusive? Or are you saying that it's fine to charge developers 30% if Apple decides the waive the $99 annual fee?
I always viewed the annual fee as more of a barrier to entry to discourage any Tom, Dick and Harry from signing up for one regardless of whether they are a legitimate developer or not, not so much a revenue stream. I would be surprised if that alone is enough to cover the costs of operating the App Store.
My thought process is this. It's the small developers who add the much-needed vibrancy to the App Store, not so much the big players like Facebook, Epic, Spotify, Netflix or Youtube. These are staples and you know they are going to be on every platform, so it's hardly a key differentiator. That's why I feel a 30% cut is not unreasonable when you look at the programme in totality.
A small developer who releases a free app doesn't need to pay Apple anything beyond that $99 each year (which is why charging by download is neither desirable nor sustainable). Those earning less than $1 million a year also need to pay Apple only 15% under their small developer programme, which is why iTunes makes sense as an efficient way of tracking how much each developer earns via app sales. The other alternative is auditing their sales receipts, which is more troublesome for all parties involved. Alternatively, they should choose to monetise via ads, which Apple doesn't take a cut of.
We also see this in a country's tax code. The more you earn, the more tax you pay, and your marginal tax rate tends to rise as your salary further increases.
It doesn't strike me as unfair that those who earn more, should pay more, and the companies that make a lot of money in the App Store are typically freemium games. These, by their very nature, tend to have zero marginal costs, and is therefore pure profit.
While Apple earns more than enough to keep the App Store afloat even if it doesn't collect a single cent from developers, I really don't see the logic where people somehow expect the App Store to be a loss leader just because Apple sells insanely profitable hardware (the corollary here is that it's somehow okay to charge developers 30% if your hardware is sold at a loss). What's wrong with striving to be profitable in every single aspect of your business?