I wouldn't put too much into that. Consoles and games sales become more and more frontloaded, so early sales tell not much.
You also have to see, that PS4 had a much more staggered launch in different region. Let's compare launch week in different regions for PS4 and PS5 (and add in Xbox for comparison):
|PS4||PS5||Xbox One||Series X/S|
|america||982,390||1,092,523 (+11%)||652,045||789,262 (+21%)|
|europe||706,948||723,341 (+2%)||311,590||349,697 (+12%)|
|japan||319,689||118,671 (-63%)||24,795||20,993 (-15%)|
This stops looking that impressive anymore, right? Playstation lost two thirds of it's market in Japan, and again: Games and game stuff tends to be more and more frontloaded. And the other markets show an 11% growth in America and only 2% in europe.
Looking at the Xbox side of things, it looks a lot better gen over gen. If anything we should talk about how Xbox is dominating more this gen. And as you mentioned: this increase gen over gen is with less launch exclusives and a lower customer base to start off from last gen.
And do you really think the market for PS+Xbox is bigger this gen than the gen before? I think it stays the same at best. So if Xbox performs better it comes at the cost of Playstation.
I admit, the ROW is missing. But VGC doesn't show them separated and I don't know when PS4 and PS5 launched in the different markets. As PS5 launched in the big markets closer than PS4, I assume that this is the case for ROW-countries too, but I don't know.
As I said, I wouldn't put too much importance into launch numbers, but if we look closely they aren't showing a massive growth or so. They show that we can a similar gen in regards to sales.