My dude, dollars is the most flattering comparison possible especially considering it's not adjusted for inflation.
Units sold through that generation dwarfs the ones that came after.
It's not about 1 console.
What was the console market like in 2007-2009?
PS3
Xbox360
PSP
DS
Wii
I don't think dedicated console hardware sales in the US will ever get back to those numbers ever again in a post mobile world.
Maybe dollar spend is the most flattering comparison possible, especially considering it's not adjusted for inflation, but I'm not questioning that in itself.
It's Mat's insistence on using these metrics to prove points in the here and now that I'm continually left shaking my head at.
Back in 2008, as others have pointed out, there were pretty unusual circumstances in the hardware/platform market. Ps2 was still lingering on doing multiple millions as well as all the platforms you mention, big point being handhelds were still an included and discrete thing. But it wasn't the golden years Mat's dollar-spend chart suggests, and there's little value in comparing now to then, especially in dollar spend terms.
Look at Nintendo - they had 2 platforms there that did a combined >20M that year by themselves. One had a very atypical and notoriously difficult to monetise userbase beyond the existing Nintendo fans that bought in by default (i.e. the grannies and other "casual" demographics buying into the novelty of the Wii), one that was far more reluctant to spend on software, the other a notoriously and widely pirated handheld. Despite obvious successes, the 2 platforms struggled in certain ways and did arguably less than they could/should have to build the industry based on their install base. PSP also suffered similarly. Half the platforms, way over half the units sold and dollars spent, all very far removed from what console gaming was and is and that suffered in their own ways... but Mat wants us to look at dollars spent on the boxes to prove a decline in console viability today. If he was genuine in his motives he could very likely come up with far more compelling and discussion-worthy talking points than money spent on boxes... especially when Nintendo are the most far removed of all form the razor/blades model of loss-leading on the hardware and now have a hybrid single-platform strategy that negates many millions of users having to purchase multiple devices and inherently spend more on them.
My point is Mat's trying (really damn hard) to suggest console gaming in 2024 is going down the shitter any chance he can, because that narrative is one he's clearly been tasked with airing. Doing so by comparing 2008 dollars spent on hardware in the US to now is an utter nonsense for myriad reasons, only some of which I've outlined above. You could say he should know better, but that's to assume he's dim and doesn't know his arse form his elbow - but that's not the case, he knows exactly what he's doing and he does it a lot of the time with dollar spend metrics because they're easy to paint the kinds of pictures he wants to portray.
As has been mentioned, that graph should naturally rise as it travels to the right, and without the anomalous 2008 era it seems to be doing just that. Not taking into account covid and what happened around then with any of this is also a big red flag.
Mat kinda sucks.