Your argument is "they are the rules".

I think the point is that the rules are anti-competitive, user-hostile, extractive.

You can make anything anti-competitive.

Spotify doesn't offer an API to allow me to replace their payment system with mine where I would direct 100% of profits to artists. Because that is their revenue source.

That makes absolutely no sense.

A more interesting/valid scenario might be something like "Spotify is using their dominance in music streaming to get too much of an advantage in the podcast market". How much is too much is for the public and politicians to debate as seen here, it's a matter of pragmatism not absolute truths.

Not GP, but I think the argument was: "IAP is easy and simple and secure and well-known, and should be used." Spotify is acting as if Apple is blocking them in many different ways, but all would be solved if Spotify would use IAP, which is super-simple for users, but doesn't make Spotify as much money.

You're saying the exact same thing: follow the rules. Completely ignoring that those rules are insane.

"IAP is easy and simple and secure and well-known, and should be used."

Is that better?

I will never use a purchase method on iOS that isn't IAP. Never, and I'm not alone.

Who cares if you prefer IAP? Use IAP then. The discussion is not that IAP is bad, the discussion is that it's the only option, hence no option. You can't even talk of other options.

I can't, because--and this is key--Spotify refuses to implement IAP! To implement IAP would drastically undermine their case, eliminating huge swathes of the linked page.

Yes, it's dumb that they're not allowed to link to the website for people to purchase directly. I would prefer that they handle it like "login with Apple," where you can support others, but must support Apple alongside. I would always choose IAP, others could click and go through the extra steps to buy directly from Spotify. But it also isn't that hard to deal with. Amazon does it for ebooks, and people still buy ebooks from Amazon by going to the website.

Spotify is throwing a fit because they don't want to even allow IAP. They want the advantages of being on iOS with zero consideration of Apple or iOS users. Apple is going too far, but if I have to choose, I side with Apple here, because Spotify is throwing a dishonest tantrum.

I understand that they find it anti-competitive but I have a problem in how they summarize their argument - they blame Apple for the cumbersome process while the real problem is them skirting the rules on IAP. The TLDR sound rather sound like “Apple wants use to use anti-competitive IAP but we don’t want to so we have to make the process of buying audiobooks complicated”. This sounds more close to the situation they describe.

When apps use IAP it’s very user-friendly. People sometimes prefer it over putting down their payment details in yet another app. I disagree that forcing apps to use IAP is user-hostile. I am not arguing that the IAP mandate is perfect, but these are the rules right now. And you can’t break rules just because you think they’re insane. Dura lex sed lex.

The "rules applied evenly to everyone" means everyone but them loses 30% of all sales revenue.

It can be perfectly legal but still wrong, in which case it makes sense to raise awareness with the public in the hope of new laws.