Windows 2000 made a very stable NT based server platform back in the day for those who wanted an Windows box. I wouldn't be surprised if there's still quite a few Win2K boxes in use. It's certainly more cost efficient than buying Windows Server 2003 or 2008 licenses, by far.
I guess Window 98 is still young. People are using it and it is still working fine.Microsoft is also providing customer service for Window 98.