"History is always written by the victors"
That may have been true back before everyone had cameras on their smartphone but Trump, like police departments around the US, discovered that saying lacks any truth.

"The campaign didn't end for [Obama] until 2014 when he finally gave up trying to do anything good."
Source?  I don't recall Obama running except for the year before his election and re-election.  Unless you are including his campaigning for other Democrats which is clearly a different situation from Trump who only campaigns for himself.