Does Apple really deserves 30% cut from IAP?

I've been working on implementing Auto Renewing Subscriptions in iOS and it's been a real pain:

• Very unclear documentation
• Flaky webhooks implementation—very limited webhooks, confusing and you can only add one URL, so if you use different URLs for different env you will have to proxy the request yourself.
• You have to poll Apple Servers to check if a subscription wasn't renewed.
• You need ugly hacks if you need to support complex subscription cases, e.g. If you have a SAAS and accounts need a subscription per project or per team member, etc.

Do they really deserve to take a 30% cut for such a bad system?