The 'target demographic' for Aurora model kits was most likely NOT going to see 2001. That same market was as likely build a model to play with as they were to make a display to sit on a shelf.
Also don't forget that the Pan Am Space Clipper was pretty much front-and-center in most of the print advertising.
I think it's somewhat a miracle that they actually picked up the 2001 license to begin with. Maybe it was 'moon landing fever', maybe it was "we do good with that sci-fi crap, what's new coming out?" logic, who can say? But the results were we got a 'space airplane' and a 'space bus' out of the deal.