How is this is a hypothetical claim? It is blatantly obvious. Spotify's early days were entirely dependent on the mobile marketplace. Even now, desktop use constitutes a tiny fraction of their total users.

It's not a hypothetical claim at all, really.

> 30% / 15% is a very steep price / revenue loss

Source? Because 30% / 15% is a common middleman commision for most platforms.

> Google provides a similar App store service

This is ridiculously far from the truth. Google's Play Store isn't curated in the least. Malware regularly pops up, the review process is effectively nonexistent, and the quality of apps on the Play Store is thus far below what one can get from the App Store.

There are costs to reviewing every app. I don't think it's fair for you to say 30% is unfair unless you (a) compare the costs to other middlemen, and (b) figure out how expensive the review process and other infrastructure is.

In general, all you really seem to be doing is promoting freeloading off the App Store. Utilize the benefits it provides, but have users pay for your service via a side-channel so you don't have to contribute back to the ecosystem.