I'm absolutely sure it's been good for Gamestop at least. Especially taking advantage of upsells on accessories and warranties and the like.

That's sort of vague and completely useless, give us some raw numbers already!

But, and I think most people will agree, MS PR has been laughably bad lately. This PR doesn't really tell us anything like MS PR. Firstly I do think the statement includes PS4 and Xbox One but the sales aren't better than them, hence using the statement 'one of the best'. I also think it sold better than the Pro and the Slims but I think we expected that anyway.

The whole thing reminds be of MS's NPD statement when they claimed Forza Horizon 3 was the best selling 1st party game for September when it was the only 1st party game released that month. 

Yes! 

PS4 and Xone launched less than 4 years ago.
Several means 3 or more but not many.
So yeah it does include those launches.

Still sony sold out on day 1. I had to wait "several" 😂months to get mine

The 3DS, psp and DS etc were all consoles too.  Specially handheld like the Switch but still consoles. 

OT: 

I'll repeat what I said earlier.  

They said one of the best launches.  They never said the best. 

Gamestop learning from Microsoft I see

But it's sold out EVERYWHERE!!

Generally speaking, several, in American English, refers to 4-7 years. So, I'm thinking he's saying strongest launch since last-gen. But, he's doing it in such a way that it doesn't actually mean anything, since he doesn't define the timeframe.