You raise a valid point, but it is a shaky argument.
PS2 was the break out after PS1 established itself as a player in the VG market. OG xbox combined with 360 still doesn't even come close to selling as much as OG PS1.
Yes, 360 has grown from xbox1, but that isn't hard considering the OG box's 22ish mil LTD.
Yes PS3 is down (relative to its very successful former iterations), but I am not convinced that that result is solely because of MS growing their user base. It is more of Sony being the worst enemy of themselves and scaring off established user base.
Now that Sony has priced themselves back into the market, we are seeing sales trends that probably would have been observed earlier if PS3 was priced competitively from the start.
This is not to say that MS has not done a commendable job in the market. They have solidified themselves as a legitimate player in the console marketplace and have taken advantage of unfortunate Sony missteps. Especially going up against an established juggernaut, I would say that they have done better than good.
Of course neither company expected Wii to be the titan it is...