I don’t know, man. I haven’t done a scientific study on it either.
It was one of the reasons why I switched from Windows to Linux. On the same HDD, with same data, Windows file manager took half a minute to open, when the various Linux file managers were all instant.
I did ‘refresh’ Windows beforehand, too, which Microsoft claims is like reinstalling. Couldn’t easily do a proper reinstall, because of OEM license horseshit.
These days, I only really see Windows when colleagues are using it. That’s all within my company’s network drive infrastructure. Maybe it is being slowed down by that.
That’s still proof enough for me, though, that Windows file manager is shittily coded. A proper architecture would have the UI in a separate thread from all the file operations and it should never be the case that a slow hard drive or network drive is causing the UI to appear later.