It did have exclusive games tho. Ryse, Forza Horizon 3, Dead Rising 3 etc. to say a few examples. And while MS was pushing more Day 1 post-2016, it was a gradual build-up for the following four years and with most of their PC stuff prior to 2020 being exclusive to their "niche" Windows/Microsoft store (which wasn't as corrosive to the console since it was way smaller than Steam AND Microsoft still owned the Windows Store).
Also of course XBO had good games; Forza Horizon, Halo 5, Cuphead, Ori & Ori 2, TitanFall...even stuff like Ryse and Dead Rising 3 were good and XBO had a better lineup of exclusives early on than PS4. Not to mention, most of the big 3P games that gen still got XBO ports, and it got certain big Japanese 3P versions Day 1 like Final Fantasy XV.
This idea that Day 1 PC was the sole or single-largest reason for Xbox's console decline, or something that was in effect at a wide scale for all of its latter life when they only started doing it for all games AND putting their games on Steam in 2020, is nonsensical. If anything, I'd say Xbox Series are finally showing the market collapse of, among other things, Day 1 on a competing PC platform like Steam for all games, which coincidentally went into effect right before the new generation launched.
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As for the OP...I agree. In terms of the sales outlook, not that PlayStation would die with "only" 70/80 million lifetime sales though. They would manage with that.
With the current strategy, Sony will probably "only" get around 80 - 90 million in lifetime sales. Which actually isn't that bad, but it also assumes they still keep getting big 3P exclusives (feels less and less of a pursuable strategy at least the way they've done it with games like FF VII Remake or the such), their 1P maintains high quality across the board, their release schedule doesn't slow down even more, and they get something like a GTA5 next gen (or at least something like a Hogwarts Legacy or Elden Ring EVERY year for the 10th gen, which isn't realistic).
More likely, Sony'll probably push for even shorter stagger windows to PC, maybe even Day 1 for all games. Even if exclusive to their own launcher, that'd probably cut down total console lifetime sales by another 5 million. But if that also extends to Steam? I can definitely see PS6 lifetime sales landing closer to 70 - 80 million. Which again, maybe doesn't look that much worst than 80-90 million, but guess what? The revenue and profits they'd get out of that 70-80 million would be exponentially less than the 80-90 million.
At the pace things are going, it's very likely Xbox Series will struggle to hit 40 - 45 million lifetime and that is with their gen going through to 2027. Considering the PS4/XBO gen was roughly 2:1 in favor of PlayStation, if SIE go down the same path as Microsoft, I can see 70 - 80 million PS6 lifetime as realistic.
