I really cannot believe how stubborn people are to defend apple on this. It wasn't that WordPress was using another service for payments within the app. They had an app, that you can use for free, which also lets you manage a bit of your website if you are hosting a website on their website. If you do not have a website hosted on their platform then you can still use the app to manage any website in the world that is running WordPress. If you are accessing a website that is hosted on their servers then even before you use this app you have to go to Wordpress.com, and setup your website. In total the app probably handles about 10% of what you need or want to do with a WordPress website. In most cases people only use it to monitor comments and uptime. You can use it to update content, but it is so gimped compared to the actual web app that most people don't use it. Now Apple comes along and they see that WordPress charges up to $1,700 to host a high traffic website, which is probably mostly going to the actual management of said website, and they say they want 30% of that for WordPress to have the privilege to publish a free app when WordPress is right now probably paying about 4% to handle those transactions. How are people not getting this.
Nothing changes for any of WordPresses existing customers, and no one is forced to sign up in app. They are also free to charge higher prices to offset the 30% if people still want to use IAPs.
Are you expecting tons of people with big Wordpress sites to suddenly cancel though WP and start paying though their phones just because?
I totally think Apple overstepped in this case, but there is no damage. We also know nothing about how they actually got here other than a few random public statements. Either way tho I find it highly improbable that Apple did this to try and profit off WP. The number of users who will actually sign up via IAP are negligible and almost none will be using any of the larger more spendy plans.