Apple just made their true target crystal clear: they have always been aiming at web capabilities: https://developer.chrome.com/docs/capabilities/fugu-showcase. We see now: they will do so until they are stopped by legal force.
Apple hides no longer behind browser engine restrictions, they are going after the heart of what lets developers deliver full-fledged app experiences without the need for native installs from app stores. Apple sees these capabilities as a direct threat to their app store model: the web IS the potential rival store diminishing that sweet revenue close to 100 billion dollars a year.
Apple loves to claim in legal debates and at congressional hearings (which is a company smell) that web apps offer a viable alternative, thus denying an App Store monopoly. But behind the scenes, they've choked browser engine choice on iOS and crippled WebKit to undermine that exact web alternative. The ability to deliver compelling standalone experiences from the web stalls because major platforms like iOS can't be trusted to keep pace with industry standards.
It's like a public transport company deliberately making their service inaccessible: "Sure, wheelchair ramps are nice in theory, but since nobody really uses our trains this way (because we never installed toilets for this user group), forget the ramps. Sorry for the inconvenience it might cause to this group who tried using trains anyhow, instead of the suggested Apple Car with our innovative iPiss system. Oh, and those pesky other train companies we're forced to allow on our tracks? You have to make your trains just as inaccessible because, uh, Apple Car is just safer to deliver wheelchair experiences!
Security is not an argument. WebKit was capable of sandboxing websites, as are Gecko and Chromium. If Apple wants to protect its users and treat them as adults, they should warn them when downloading browsers, that is it. If you want to play apple safe, stay by Safari. You do not need web apps, anyways. Your system is not in danger if I download “shit” on MY iPhone. In addition, Apple is capable and it is not an unreasonable ask to make iOS secure for web browsers. Every other OS, including their own macOS, does this.
It's baffling how Apple underestimates the intelligence of judges and lawmakers. Should Apple try to cripple web capabilities for alternative browsers (directly like the current plan is or even subtly with keeping iOS sub-optimal regarding web app security), may those fines come and let them be staggering. Apple choked web capabilities with WebKit and now does this directly by misusing the power of iOS. Apple shouldn't get to block the web alternative to their App Store while pretending to offer one on legal battlefields.
For web apps you need developers who are not threatened by Apple and iOS to pull the plug on their product any time. Like they are trying to do now. Web app usage and adoption would also be boosted if the developer community stopped calling “install” what is a switch from tab to standalone mode. Using the word "install" undermines not just the inherent simplicity of web apps but the long established trust in the safety of browsing websites within a controlled tab. The word "install" creates a false sense of heightened risk and potential device alteration. This creates unnecessary confusion and suspicion, hindering user adoption. We should build upon the success of the web, emphasizing the truth that web apps are simply enhanced websites and leverage the implicit trust users already place in the web security model.