I would bet my 2 Euro, that it is because people just don't have a need to buy new PC ever year, because computational power did not really went up in last decade?

i.e. I still have my Lenovo E520, which I bought in 2011, after putting there SSD, new battery and more RAM, it works just fine with Windows 10 until today.

I still have my desktop computer with Intel i5, bought around 2013, still working with Windows 10, I have it more-less as backup PC. Got new one around 2019 with AMD Ryzen 7 and I feel no need to upgrade for next few years. Because why should I do it?