Vista shows how important the initial reputation is. Everybody had made up their mind to hate it, even if the hate wasn’t fully justified. There wasn’t much Microsoft could do about it, other than releasing Windows 7.
Windows 8 on the other hand was genuinely bad.
Even when computers did improve and became able to handle Vista people weren’t willing to change their minds about it. Windows 7 had a 1GB memory requirement. Why didn’t more people use Vista right before the Windows 7 launch?