The problem there is end of the day Apple made a major security hole from the beginning if they could not popularly sandbox a browser engine from the beginning. Instead they took short cuts and cheated with security risk of deeply integrating webkit with out proper sandboxing. You would of though Apple would of been smart enough to not make the same mistake MS did with integrating IE to deep into windows.
Cost wise yeah might be a little high but end of the day Apple screwed up in the late 2000's with that decision and instead of trying to fix that security problem they left it in their for years.
That might also explain MULTIPLE security holes in the past that allow people to root the phone threw safari because let the browser get way to deep into the system. Still they never fix root security problem it in over 10 years.
Root problem is not sandboxing the web engine. Sad they did not learn from the mistake MS made in 95.
This entire comment is one non sequitur after another sprinkled with assumptions without any basis to support them.
Safari
is sandboxed, just like other browsers are sandboxed, and just like apps are sandboxed.
The problem isn't so much the sandbox as it is the need to rewrite the underlying architecture to facilitate escalated privileges that manage the installation to the home screen and that allow for background processes by browsers to be run, all in a safe and manageable manner.
On top of that, as it was pointed out, they need to ensure everything remains compatible when the OS changes but also when the browsers change.
They've done the legwork for this with Safari, which, while challenging, is manageable because of direct lines with the Safari and WebKit team.
Having to redo the legwork in such a way that it is agnostic to which browser is involved and maintaining compatibility with the other vendors is an entirely different ballgame and Apple has decided that (for now anyways) it's not worth the trouble, especially in light of all the other efforts they need to undertake.
Instead of leaving it as is, giving themselves a benefit over competitors, something the DMA doesn't allow, they've chosen to disable it for Safari as well and change it into a bookmarking function.
Completely reasonable of course, because the install rate of PWAs, even across other platforms such as Android and Windows, is negligible.