That and MS Office are pretty darn popular. Not the whole world, but a very decent percentage of your users.

Certainly enough where this is embarrassing incompetence by them.

No, just over 6 million paying business customers.

But hey, if you're in a business domain where categorically leaving 6 million potential clients-who-are-demonstrated-to-spend-on-things isn't an issue? One fewer thing to worry about, right? ;)