running the stuff people want .... Windows does so, Linux doesn't.
Depends on the people, depends on what they want.
You could invert that sentence and swap "Mac" for "Linux" for many audiences ; particularly creative types that have specialist apps that only run on one platform.
For simple uses... there's no problem. Linux has browsers, email clients, and LibreOffice. For business purposes, anything written in Java or one of the other virtual runtimes should be easy to port to Linux, or run right out of the box.
For complex uses... it depends on the niche. Certainly for software development, Linux wins for basically everything except native and .NET Windows apps. For other uses, I will grant you, the professional-grade applications are not available (even if they run in Wine). But I'm not an artist. I'm a developer.
Gaming is one of the things that keeps Windows on my hard drive, but Valve are trying their darndest to make this irrelevant. I'm watching with interest, but Windows won't be going away just yet....
But that's it. All my real work is done on Linux. Windows has been relegated to the status of a toy for me. I find it frustrating and clumsy to work with - even more so once the IT department has shackled the vast suite of corporate malware they deem necessary to the chain around it's neck. The software I produce is a mixture of server processes and client tools that run on both Windows and Linux. I even *gasp* pay for software to run on Linux.
I agree there is a vast technical debt built up apps written on platform-specific toolkits, but they become obsolete eventually and there's no excuse for porting them to another platform-locked toolkit any more.