I completely disagree with you.
An open online competitive play is better for the consumer / customer and that is the only thing the company should be considering. The only real issue I see is name clashing, but I'm sure that could be worked out behind the scenes and then be transparent to the user.
You as a consumer shouldn't care if Sony/MS/Nintendo is leading in sales... what you should care about is the content and benefits you are provided. Being able to play anyone from any type of environment is a good thing. It will make online games match-making faster and various online games have longer lives as the available player pool is larger.