So both MS and Apple teams may focus on what is "right" and avoid feature bloat in UI, avoid quick and dirty solutions etc. Yes, they must include some features quickly and efficiently to allow support for some new APIs in the new products. But the overall design and fit and finish is free to define however they want. They can spend time making it right and redoing it how they please. They have resources and expertise for that and they don't need be in a stressing "competition" mood.
I'm really disappointed by what Microsoft did with Visual Studio. They have great technology - great language, great compiler support and integration with editors. But the way it is all presented and organized is all boring mess of panels and tons of icons. They even understand all the icons are heavy for eyes, but instead of rethinking the design, they simply ask "40 existing and 36 new VS users" how do they like monochrome versions.
Apple's Xcode 3 was also a messy window/panel cluttered tool like many others. Many still considered it lighter than any other complex IDE, but it was fairly cluttered on its own. Next version, Xcode 4 was not designed by "asking developers". Developers want a pink pony and all the features in one click. Xcode 4 was designed. They made priorities and straightened UI so much it is now Plain Straight. One window, three panes, 7 buttons on toolbar. Just by learning a single screenshot with both sidebars opened, you already know how to navigate 80% of the time. It is crucial. You don't have to read huge manual to learn more and more useful things. They all are discoverable over time. Most important things are more visible, others are discovered over time.
Apple and Microsoft are rarely in position to throw old stuff out and replace it with brand new in their actual products that make money. Windows, Mac, iOS all have its legacy which must be dealt with. But UI for developer tools are different and Microsoft has no excuse not to make it interesting. Unless, of course, they don't want to maintain their own engineering culture.