That video link I posted above has information that a western poll company recognized by the US pegged Putin at 80 to 85% Putin BEFORE the election. Why do you not believe that it is not possible that Putin won by the margin reported? International observers were there too, despite being threatened by the US, but that’s a separate story in itself.
In the United States, the international observers of American "elections" might end up in the DC Lubyanka, for a show trial like the Soviet show trials of 1937...
Putin won because his only serious competitor was murdered. The other candidates had no intention to win.