For instance, to be competitive in terms of performance, a browser almost certainly needs to JIT Javascript. If a platform prevents apps from generating code and enabling the 'X' bit in PTEs then this isn't going to work. Even if the platform provides JIT services (e.g., pass in an AST, out pops a few pages of callable code) there is still a ton of added risk.
Designing and maintaining the security of a platform is a ton of work and a big investment (assuming it's done well). Security teams are already quite busy, and adding whole app categories that are suddenly able to break previously established design decisions is not easy -- "just do a security audit on a handful of titles" is a phrase that we've all heard, many times, and it sends shivers down our spines. Having seen it tried, and been on some projects that did it, I think it's impossible to do well even at a small scale.
Been there, done that, seen projects canceled because PMs couldn't internalize the nature of the risk to the platform.
A large part of Apple's brand, at this point, is security from snooping, personal privacy, etc etc. It makes sense to control the browser on the iPhone for privacy than it does to seek to eliminate browser competitors. Safari isn't a crucial part of their revenue, devices with the security promise are. Furthermore, the browser seems to be the key space where use privacy is violated from, via cookies and other tracking software. If Apple want's to say they have a pro-privacy device, controlling the browser makes sense for that goal.
It just doesn't make business sense for Apple to be attempting to control the browser market. Maybe you mean they are controlling some other market through the browser, though.
Moreover, when one is selling something that involves transferring all rights in tangible/real property being sold to be transfered. Here apple is reserving the right to decide what can and cant run on the device. This clearly is a violation of property rights. Last I checked apple did not have people sign rent/lease agreements for the hardware.
I'll be the last one to prevent you from running your own software on the hardware you bought. So, knock yourself out: Wipe all the nasty, evil Apple software off of that device and have your way with it. I would not expect any help from Apple about how to do this.
This argument is straight up disingenuous- Apple is actively preventing you from running whatever you want on your property and they are preventing you from repairing it. You cannot get them to remove their crap from it.
Conjuring up some arbitrary boundary constrains device maker innovation, reliability, security, and other consumer value.
You are free to pick your own water line, find a device that draws the line there, and vote with your wallet — or make and market your own thesis.
This about not allowing competing browsers as a blanket policy. If this was trully about security, Apple can do as many security audits as they want. They can even charge for them. They can require affidavit, security officers, insurance policy, indemnity, etc.
But they dont because this is not about security, it is about controling the market