So Sony expects PS5 to be outselling PS4 by September 2023 or so.
Just to have some real numbers, at the point where PS4 and PS5 intersect on the above graph, PS4 had sold roughly 50m consoles. This means Sony expects to sell close to 30m consoles within a 18 month period.
In the current fiscal year they will be selling Horizon 2, GT7, MLB, Ghostwire, GoWR, multiple TLOU stuff, FFXVI, Forspoken, the PSVR2 launch stuff and markeing with 3rd party multi stuff like CoD, Howgarts Legacy, Avatar, FIFA, NBA2K and more to be announced, plus other multi superseller stuff like Elden Ring. Plus also have their refurbished game sub which will improve a lot its numbers.
This huge amount of super sellers in normal conditions this would be a super strong year in hardware sales. In addition to this, we know there is a monster demand of people who wants to buy the console but can't.
If they had enough chips, they would sell more than these 30M in a year and a half, even in less time. The amount of hardware sales will depend on chip availability, because there will be more than enough demand.
Last year they were promised a certain amount of chips that they didn't receive on time so later had to lower their estimations. We're seeing now apparently way more shipments than usual, pretty likely because these are the chips promise to have on time for the previous FY but were sent with a 2-3 months delay. Maybe they managed to correct it and as compensation for being late last fiscal year the chip manufacturer will give PS5 more attention this year so will produce more chips for it than previously planned, who knows.
Not to mention that by then Nintendo is likely to kickstart the 10th gen and Sony and MS will have to deal with that too.
I think it's laughable to count Nintendo devices a generation ahead of the other ones that are in the same timeframe and have way more powerful hardware.
In this case, I think the Switch successor, lets call it Switch 2 or Super Switch, I asume will have the hardware that was leaked and being called "Switch Pro" by the fans. Basically a Switch but slightly more powerful and capable to upscale their games to 4K using that Nvidia tech. This would make it BC (addressing the concern shown recently by a Nintendo exec) with Switch and would fit inside in that extra long lifecycle the Switch is going to have according to their execs.
You and others will consider it a "10th gen" device, I'll consider it as the same gen than PS4 Pro and XB1X because will have relatively similar specs and won't be able to run top tier (in tech side) PS5 and Series X AAA games.
Btw, according to you how is decided that a new generation starts? In which generation is the Playdate portable included?