not bogus just based on volume of useage.
And autocad sells more than anyone else, it's why they can afford to produce and give away all the 123dapps stuff.

Autocad is general purpose, most of the others are more niche.
I'm not saying autocad is better - never got my head t=round any wysiwig cad. But it is the most widely spread among a lot of industries.

No one has ever asked me to try and 'acquire' a copy of any other cad software. Kind of speaks for itself really.