Windows is closer to irrelevant now than ever before. Many people use non windows tablets and phones far more than desktops. Some websites see far more non desktop users than desktop users so arguably their market share is under 50%.
For a more direct comparison Windows phone has 5% of iOS market share and 1% of Androids. Most major software news is off Windows Instagram and Pokemon Go for example really don't care about the desktop. The web got good enough that many services are native on mobile and Windoes just gets a website.