Duh, yes they'll get the message if their PC sales drop to nearly non-existent, while the versions not bound to that crap sell millions. Or did you miss how Ubisoft changed their Online-DRM politics lately? Already forgot how their PC share fell to a single digit percentage?
The console versions will always outsell the PC versions, regardless of whether the PC version uses GFWL. As such, publishers expect PC versions to sell less. If you boycott the PC version but buy the console versions, you're only reinforcing this expectation.
A much more effective tactic is to boycott the game for all platforms, forcing the publishers to reconsider their business decisions all around.