Windows Latest did some digging and found an explanation in an April 2022 Windows Insider AMA, given by Tali Roth who managed the Windows core user experience at the time.
The biggest issue was that Windows 11 didn’t carry over large parts of the old Win32 code, which included the ability to move and customize the taskbar. Microsoft had to rebuild the taskbar from scratch and focused only on the key aspects that needed to work for Windows 11.
In the process, it became clear that moving the taskbar wouldn’t be a trivial feature, primarily because all the apps contained within it would have to respond and adjust accordingly—and the new Windows 11 framework didn’t allow for that.
“When you think about having the taskbar on the right or the left, all of a sudden the reflow and the work that all of the apps have to do to be able to have a wonderful experience in those environments is just huge,” Roth said.
Microsoft also said that demand for a repositionable taskbar was low, as most users tended to opt for the default option. Only in the years that followed did it become a more prominent issue, with a small but vocal audience of Windows users repeatedly pointing at the missing feature and asking Microsoft to bring it back.
To make the taskbar repositionable again, Microsoft carried out various tests with Windows Insiders until they got a desirable result.
The same was true for the Start menu, which previously offered significantly more customization options in Windows 10. Given Microsoft’s design direction—a cleaner, more minimalist look that leans more heavily into smartphone philosophy than desktop—it wasn’t easy to add customization to the Windows 11 Start menu.