The PC market's decline will last, at least according to Microsoft, which is a factor in Windows OEMs' 39% decline. OEM refers to major hardware manufacturers such as HP, Lenovo, and Dell that sell PCs with Windows installed.
Given that there hasn't been a major shift to Linux, the data is troubling in the sense that the decrease in Windows sales is certainly related to the decrease in PC sales.
Microsoft itself cited the "current decline in the PC market and a very strong previous year" to explain the decline. Nevertheless, companies such as Canalys reported a decline in the PC market by 29% in the last quarter of last year and 16% in the whole of 2021.
Microsoft expects a 30% drop in Windows OEMs in the first quarter of 2023, but it's likely that sales will return to pre-pandemic levels.