Why would different business practices shield console makers in the first place, legally speaking? As in, even if all consoles were always sold at a loss, how would that help someone's legal case that they should be excluded here? Does the law state that, "if your business practices are incompatible with antitrust legislation, and you'd end up having to raise prices, shut down, or decrease your CEO's paycheck, if we enforced it on you, then we won't do it" or something along those lines?

Except there are indeed productivity tools for consoles as well, e.g. anything done with UWP on Windows Store can also be targeted to XBox UWP ERA environment.