I was actually thinking about this the other day, coming up on 10 years of membership soon
When I was in high school, I wanted an 850 Turbo
When I had the money for one last year, no clean ones were to be found so I bought the V50 instead - a lot of the P80s were bought as throwaway cars by people like me 5 years ago (case in point, I trashed my 1 owner, low mileage manual 97 NA)
As a performance platform the new cars just aren't affordable enough yet and the older ones have people like me in the mid-to-late twenties saying 'Monkey that, I need an Amazon subscription of PB Blaster for this car - if I'm going through all this hassle it will be for something worth it
I would also wager that enough of us have tried to turn these luxo barges into performance cars and run into the plethora of problems that come when you try to force a car to be something it was never designed to be - anyone who wants a fun car won't buy a Volvo and we've all tried it and still hang here to scare people away.
I'm split between Volvo and VW - the aftermarket (mods & parts), supply of decent preowned ones, and wrenching ease is up for the MK4 (1999-2004) VWs as these are just reaching the bottom of the depreciation curve much like the 850s and S70s were 5ish years ago...
Also, the dealer only subscription software and lack of manual transmissions has all but forced me to buy a VW