2020-2021 pulled forward sales that now aren't going to happen for a few years. Add in a bad economy and people will just make do with their existing devices a little longer.
And considering existing devices are still so bloody good, that likely dampens upgrade enthusiasm a bit.
Speaking for myself, I have decided to not replace my 2020 iMac 5K with an M2 Mac Studio, but instead use my 14" M1 MacBook Pro since it is more than capable of doing the job. Also likely going to keep my iPhone 14 Pro Max and skip the 15 model. And am going to hold on to my 2018 iPad Pro 12.9 until the OLED models arrive.
So that is ~$5000 worth of Apple kit I am deferring from 2023 to 2024 because even though I could easily afford it, the value is not there for me.