My company's SaaS product used to have an iOS and Android app which we discontinued a couple of years ago when Safari finally started supporting more web-standards that enabled our PWA to more-or-less have parity with the old app (confession: our app was using Xamarin instead of being truly native, not that it mattered much).
...so with that context in-mind, we don't benefit from - nor really need at all, most of those services you're referring to;
> Bandwidth
We're a small B2B SaaS with a userbase sized under 100,000 users and our old app bundle was around ~20MB and updated a handful of times per year, so even if 100% of our users used the iOS app with auto-updates then that's less than 2GB of data-transfer per published update - the cost of serving that is far less than a rounding-error on AWS/Azure.
> Running the App Store for users
I accept that.
> Marketing the App Store
No-one should be paying for Apple to market their own App Store - and as a B2B SaaS app, Apple would never promote us or do marketing for us.
> App review
I also accept this - but ostensibly this is what your $99/yr developer fee pays for.
> Security efforts to keep malware off the store
This is the same thing as App review; if we look more broadly, then it's better to compare this to Microsoft's Windows Defender which is free, and is funded independently of the Microsoft App Store.
> Making App Store optimisation tools for developers
Again, this is Apple's responsibility to pay for, not ours - and even-then consider that efficient update/patch distribution systems have been around for decades so it's hardly cutting-edge development (e.g. those ~KB-sized binary diff patches for CD-installed games in the late-1990s when we were on dial-up, like EA had for SimCity 3000 or C&C Red Alert 2)
For a B2B SaaS client app for BYOD users the iOS App Store is perfectly fine as a distribution system, and morally I'm fine with paying Apple some kind of fee for the benefits of their distribution system, but Apple has no legitimate claim to any percentage of the subscription fees we get from our users - so what this means is that we can make our app available for free to our users (which is fine, honestly) but (as per my understanding of the rules) we cannot offer any kind of account-management or billing-management for their SaaS subscriptions from within the app which isn't ideal.
I think Apple's main mistake here was deciding that having a single set of rules and fee-schedules/commission/etc for everyone, because the revenue models for exploitative mobile games (especially their gold/gems IAPs) differs massively from my company's unimaginatively dry B2B SaaS client.