I think had the AAA Amiga actually appeared it would of also helped the Atari Falcon. The problem with the Falcon was that it was floating around alone once released, with little support. Had another generation of Amiga been released to directly compete with the Falcon I believe the industry for the two machines would have continued along the same path with the fans of both the ST and Amiga continuing to buy into the new generation of hardware. Developers would have had two platforms to cross develop for and felt secure about the possibility of profit from software development. Instead the Falcon wasn't popular because of a lack of support, but also because it didn't really fit in anywhere and the PC hardware was quickly moving forward at a fast rate (all be it much more expensive).

I never thought I would come to the conclusion that the existence of the Amiga help the sales of the ST! But it is true. Competition in the marketplace always goes this. If a system is alone in the marketplace it tends to stagnate and not generate interest.