How harmful would it be for them to pay a small team of photo nerds to surf the web all day and find out what buyers want?
Because people posting in forums are not necessarily buyers, or at least there is hardly any connection between internet opinion and sales, the latest example is the underwhelming but popular 6d.
What happens if you ask buyers about what they want you can as well file for bankruptcy right away like when Homer's brother let him design a car: http://simpsons.wikia.com/wiki/The_Homer
And another example highlighted above. Only a small number of people in Canon know whether the 6d is "popular" as far as meeting expected sales figures. And a similar small number know whether the "underwhelming" view of the 6D is just from crazed internet forums or actually the view of the camera buying public at large.
For example, I think the 60D was under-speced, with the deletion of MFA a big mistake. I also think the 6D should have had an AF system at least as good as the 60D. But unless someone at Canon shows unusual candor, we'll never know if they agree with these points, or if they even acknowledge that these issues affected sales of the cameras.