Google Movies and Disney+ can be watched on their app though. They are still "reader" apps.
Buying/renting you can go via their site and I bet they prefer that for at least Google. They get all that customer info and no cut needed.
Any previously purchased items are available on the apps it is just in-app purchasing is usually turned off to prevent the iOS 15% cut for "reader" apps. They could have it on and available to use Apple's Appstore to rent/purchase but the in-app purchasing fees apply 15%/30% depending on the content and app classification.
Pretty easy to just purchase online and then watch in the app.
Games will always be 30% most likely because iOS is a gaming platform as well and that matches other gaming store cuts.
Even Tencent was 55% at one point for MyApp, they came down to 30% inline with other markets in 2019. Tencent MyApp is a competitor to Appstore in China, both companies make about $16B on their stores in revenues. If anything Apple/Google/Steam/etc all forced Tencent MyApp to come down to 30% from 55%. So things could be worse. Cuts prior to app stores were in the 60-70% range for gaming which was absurd.
Epic Game store is 12% (was previously 30% but they lowered to compete on price) which Tim Sweeney has said profitability is around 7-8% but they only allow in games that you have a deal with them. They don't allow just any game to be sold which adds lots of additional cost. Apple, Google, Steam etc all allow in any game which is good as long as it meets their ToS. Mobile really opened up gaming markets and that is industry standard now. Apple/Google even forced Steam to open up about 5 years after the mobile stores appeared.
My guess is break even for stores is about 10-15% if you have a more open market for all, part of that is keeping the stores/games secure from malware and payment info protected. That is why Apple was willing to go to 15% for small business and does for "reader" apps. They aren't making a ton of profit on those.