I wouldn't quite say that. It's dangerous to say one brand is stronger than the other just because reasons. There are factors tying to products under that brand umbrella that incidentally increase the power of the brand, but the brand itself has no power.
I mean, people used to say this same thing about Nintendo. Then Sega came and wrecked things up in U.S and Europe (and Brazil). Then Sony came and did that globally, and also knocked Sega out of the race in due time. The PlayStation has already proven it's not infallible, even when everything's on a fair playing field, otherwise the XBO would not even be an afterthought in the US and UK at this point of the race. I mean, Sony probably thought the same thing: PlayStation was infallible. That's how the 360 got to eat so much mindshare and marketshare in the West, b/c that thinking made them rest on their laurels. I'd rather Sony not do that again, because we're seeing Microsoft pay the price in thinking that about the Xbox brand in the West.
When you strip away everything aggregated to PlayStation and Xbox, they are worth exactly the same: worthless. These companies have to work to get the sales, and Sony has simply been putting in more work. Twice as much in fact, that's why they're 2:1 (if not 2.5:1 by this point) in sales WW. And it looks like they and their partners will continue doing so, increasing the workload even.
Point being, PlayStation doesn't sell consoles the way it does simply for being PlayStation; they put in the work to justify their existence worthy of those sales.