Re: surely of rather more note?!
"anyone doing real work is using Apache or nginx"
These market share numbers were near universally quoted when Apache was #1. Now IIS has taken the throne suddenly now we have to fudge it by categorising what the sites do lol.
I think what is really going on here is that a significant subset of commercial users are fed up with being continually hacked and exploited when using open source web stacks, and have switched to Microsoft IIS because of it's far far better security record in recent years. And it's much easier to setup and use - no prehistoric editing of text files required...