Re: Dear gods...
BricsCAD is major - BRL-CAD also has a very large user base ;)
By your definition, Microsoft Paint is a "major" graphics application simply because it's installed everywhere... Talking of graphics, everyone seems to think that Adobe's suite is best run on Windows these days, not Mac.
Whilst I'm sure it's fine, you would not use BricsCAD to design an airliner, or a ship, or a car, or a skyscraper. For that you need something like CATIA. They do not do Linux versions of their software. According to Wikipedia they do nominally support Solaris, AIX and HP-UX, but since no one runs these as desktops these days it's Windows all the way.
It's a similar story with other major CAD packages like SolidWorks, the major parts of Autodesk's portfolio. Casting an eye round Mentor Graphic's suite suggests that Linux support is old / out of date, and that they're predominantly Windows these days.