Windows 10 may have breathed new life into your PC, but it didn't do anything to juice PC sales this summer. Both Gartner and IDC estimate that computer sales dropped several points year-over-year (between 7.7 and 10.8 percent) in the third quarter, right when the new Windows arrived.
I think a lot of people are waiting for Windows 11 because they are not happy with Windows 10 design, and features, and they recently bought or build a Windows 7 computer which works great for most tasks.
I agree it is a bad time to buy a PC when Windows 10 just came out because there may still be a lot of unfixed problems which needs to be fix with a Windows Update release in the future.