Well so far it indicates otherwise.

So in the first 6 months of the year, the PS5 sold x2 consoles than the Series X/S

I'm pretty positive he's talking about the gap between ps5 and Series X|S will be less than the Ps4 and X1, which is entirely possible. 

Weird way to put this then, cause he said (and that's a direct quote): "but I expect the PS5 to sell less globally than the PS4"

"I expect the Series S/X to outsell the Xbox One globally, but I expect the PS5 to sell less globally than the PS4. The lead Sony had in the eighth generation will shrink."

When I read the entire sentence and not fixate on the part about the ps5 and ps4 comparison, it's really not weird. 

It's still too early to make any long term predictions at this point. Clearly, the PS5 is more in demand at launch than the PS4 was.  The real test will start in September when PS4 weekly sales really started taking off. Can Sony produce enough PS5s to have multiple 300K weeks by then, and nearly 1M units on Black Friday week?  Time will tell.

XBox Series X/S should comfortably outsell the One most weeks right up until the holiday season even with current production.

Personally I think both consoles will outsell their predecessors, but the Xbox by a little bit more, if no other reason than it has a lower bar to clear than the PS5 does.  And I think both will do better because I think the past year will have a long-term effect on video game demand that will boost this entire generation.  Not saying that COVID itself will last years, but that the lockdown periods got more people into video games that will continue to enjoy them even after COVID ends in all parts of the world.

That's why I'm talking about lifetime sales, not using less than 8 months of sales for that projection.  

Are you both thinking "end of the year" means first 12 months from launch? end of the year to me means calendar year, or the end of December.

By VGC at the end of 2014 PS4 was at 18.2m & XBO was at 10.3m... I know they are struggling with demand at the moment but I highly doubt there won't be some level of stockpiling for the holidays, so with both tracking ahead of predecessors id say you are both predicting too low for both consoles. Ignoring any adjustments my current prediction would be 11m for X/S & 19m for PS5.

I expect the Series X/S to be around 11-12 million and the PS5 at around 18-19 million.

Ah ok, that makes more sense.

In which case yes 15m / 10m seems about right.