OK so if I buy clothing from Target using their iOS app Apple should get 30% of that transaction?
Its not about "should" or "shouldn't", its about whether Apples terms are worth it to each company.
Apple states, up front, "here is what we offer, here is what you have to pay to use it". Either thats worth it to you or its not. If its not, thats perfectly fine and valid. Target could absolutely say "We don't think a 30% commission on sales is worth it, so we won't make a native app, we'll use the web instead". OR they could say "we'll get way more customers with a native app, so the 30% will be worth it".
No one is forced to make an iPhone app. Alternatives exist, including the web and Android. If Apple had monopoly power it would be different, but they don't. Apple offers an opportunity and its a free choice whether someone decide to try and use that opportunity or not. Thats how it should work. Apple offers terms, developers can either agree and make an app, or disagree and not make an app (or alternatively disagree, try and convince Apple to change its policies).
In areas like these the only things that "force" Apple to change should be market pressure (i.e other platforms offering better deals) or customer pressure (i.e. people not buying Apple products because they can't get the apps they want for it). Otherwise? Apple should charge whatever cost or fee it feels is reasonable and devs can take it or leave it. Courts and legislatures are ill-equipped to deal with technology issues like this and should tread lightly absent proof of actual harm. Given very little (if any evidence) consumers are harmed by Apples approach to IAP (which is no different than Nintendo, Microsoft, Sony, or pre-smartphone phones) and many examples how they benefit (trust, privacy, security, convenience), the courts and legislatures should stay in their lane and stop trying to force Apple to change just so some other company can take that money instead. Consumers are still going to be forced to pay, it'll just be less convenient, secure, and absolutely ignore their privacy concerns as has been shown many times in other areas.
Users (and developers) already have a choice. Use the web, use an Android device, use a Mac or PC, etc. Leave the iPhone alone. Many of us are quite happy with the way things are, in fact we prefer it.