They could also implement that independent of the injunction, which applies to steering rules.
They actually can't, not with the latest ruling that unlocked this Kindle change. Apple annoyed the judge enough with their shenanigans that she shut this down, too. The ruling reads (emphasis mine): "Effective immediately Apple will no longer impede developers’ ability to communicate with users *nor will they levy or impose a new commission on off-app purchases*."
You still need that to get on the platform. They could charge based on the relative size of the business. Why not charge Netflix 50K? They won't give up the platform and the consumer - even for Netflix - likely wouldn't enjoy going to the web browser exclusively.
Perhaps that pushes more PWA's but really, I doubt the big corps would balk at this.
Their scale would need to be exceedingly reasonable to keep the smaller shops from rioting though.
The justification would be something like, "a more equitable and transparent system that aligns costs with platform usage and developer access to the user base, while also potentially fostering a more diverse and competitive app ecosystem" (generated)
Apple wants to mandate a review? That's fine. Charge developers for the reviewers' time with a reasonable profit margin, and Apple _already_ charges $100 a year for access to the AppStore.