Earlier quoted context omitted.
If you don't sell in Idaho, you lose that market. If you don't sell on Apple's platform, you lose that market. The issue is a combination of the "tax" and the market dominance of these two companies.
...okay? I'm asking why oneplane completely disagrees with using the word "tax" here.
If you consider the Appstore/iOS ecosystem to be Apple's "land", then sure that 30% is like the tax for having a presence in that land.
That's the classic meaning of "tax".
However, nowadays, in most civilised countries we expect more of "tax". We expect it to not simply flow to whoever holds power over the land (ecosystem), for them to use for profit, projecting power and keeping it. We expect the tax instead to largely be invested in things that benefit the people paying it (users). In fact, the more this happens, instead of going to the rulers, the nicer a place to live (in general).
Now one the one hand Apple is doing a pretty good job with things that benefit the users: they get security and some privacy. On the other hand, as a tax, it's fair to ask whether that 30% is really necessary for these benefits or just for lining Apple's pockets. An additional thing, looking at it pragmatically, whatever Apple's doing to Spotify doesn't seem to be in the user's benefit at all. But then, they don't pay tax. So that points to the 30% being significantly more than the tax required to benefit the users.
It seems to me that Apple should lower this tax to a rate that Spotify is willing to pay and put up with.
Thing is, Apple is not really like a modern government to its users. They are a "if you don't like it, just leave"-ocracy. So when they put up a "public" service (Apple Music), that undercuts commercial services (Spotify), it is NOT in the benefit of the people (users) like a public transport system would be. This is because the undercutting is purely based on the tax-cut, not because it's more efficient to do it as a public service rather than a commercial one.