It could be more interesting to look at all the consoles, not only the playstations.

N64/PS1/Saturn: 146 million units sold worldwide

GC/PS2/Dreamcast/Xbox: 214

Wii/PS3/Xbox 360: 275

WiiU/Switch/PS4/Xbox One: 338

Switch 2/PS5/Xbox Series: 150

So since only the last generation has lower number of units sold, it seems to me that the market for console is either only recently declining, or the cycle is much longer and people takes more time to buy the new generation.