But it is technical. IE, Chrome, and Firefox are different codebases and what's true of one isn't necessarily true of the others.
Chrome and Firefox are largely self-contained. Being multi-platform, they have to be. It makes sense that they can be modified without touching their underlying operating systems.
You keep calling IE "Browser" but it's more than that - it is (or at least used to be) a core component of Windows, and very tightly coupled with parts of the operating system that have nothing to do with web browsing. (Navigating local files, for one thing.) Consequently, overhauling IE without overhauling Windows is (or at least was) a hairy proposition and Microsoft decided it wasn't worth it.
I don't know about DirectX, but I suspect it's also tightly coupled with the operating system such that it's not technically feasible to make current versions run on differently engineered operating systems.
> it is (or at least used to be) a core component of Windows, and very tightly coupled with parts of the operating system that have nothing to do with web browsing. (Navigating local files, for one thing.) Consequently, overhauling IE without overhauling Windows is (or at least was) a hairy proposition and Microsoft decided it wasn't worth it.
That's the company line, they even stated this in court. It might be true today, but I seriously doubt it -- it was definitely NOT true at the time they stated this in court. It was put into the OS with duct tape, definitely not anything at any "core".
I saw a demo of 98 or ME or XP (don't remember which one - the first one that came with integrated IE4) with the web control disabled; some "web folder" views and "active desktop" did not work but the older win95/2000 "folder view" did. If you did not use ActiveX, you didn't feel anything amiss.
In the default setup, if you browsed a local directory through "iexplore.exe", it would fork "explorer.exe" opening another window unexpectedly, although "explorer.exe" would not fork one for a web view (but folder view->web view->folder view did again). Definitely felt like the work of someone who had no access to the "core" to integrate it properly.
If you believe that NOT supporting a newer Trident engine and IE shell on older OS is anything but a political decision, I have a bridge to sell you in Brooklyn you might be interested in. Sure, it costs more to support - but it's a rounding error in Microsoft's development budget.
Finally, even if the "core" issue is true, which (as I stated) I have issues with, the architecture lets them easily keep the old "web component" in the core, and only use the newer one from the IE container. The decision is political in every possible way.
Here in 2014, who cares? It, by being on every system, provides considerable benefits for developers and users--as far back as .NET 1.1 I was able to drop a WebBrowser control into a form and get exactly what I wanted.
The idea that a browser shouldn't be integrated into an OS makes no sense to me, and apparently to everybody else shipping an OS anyone cares about. OS X has an integrated webview, too, and you can't pitch Safari out the window.
Chrome and Firefox are largely self-contained. Being multi-platform, they have to be. It makes sense that they can be modified without touching their underlying operating systems.
You keep calling IE "Browser" but it's more than that - it is (or at least used to be) a core component of Windows, and very tightly coupled with parts of the operating system that have nothing to do with web browsing. (Navigating local files, for one thing.) Consequently, overhauling IE without overhauling Windows is (or at least was) a hairy proposition and Microsoft decided it wasn't worth it.
I don't know about DirectX, but I suspect it's also tightly coupled with the operating system such that it's not technically feasible to make current versions run on differently engineered operating systems.