I live in the real world. I use the tools I need to communicate with who I need.
When a customer asks for a Word Document, I deliver a Word Document. When a customer asks for a 200-page print-out, I deliver it however the hell I feel like it. I'll deliver it using InDesign if I believe its the best tool for the job.
Here's why Microsoft Office is used. Because it works. Sticking with a standard office font works across Mac, Windows, and yes, even Linux (thanks to Crosstools). Abiword and OpenOffice are much better at reading Microsoft Office documents than they are at reading each other.
But when it comes down to beautiful typesetting, semantic markup and the like? LaTeX is quite hard to beat.
When it comes to opening up a 25 year old document and it still looking exactly like how it was typeset in Word 95? Well... Microsoft actually has accomplished that quite decently. Tell me, does Libre Office support the StarWord format as well as Word 2013 supports a Word95 document?
On the other hand, LaTeX supports documents from the 80s quite well, ditto with TeX.