The revisionism its strong in here. It goes to the point of downplaying what Mourinho has done at Porto and Inter. With Porto Mourinho not only won back to back championships - ending Porto 3 year trophyless run - but also won back to back european titles: the Uefa and the Champions League. This with a team that costed peanuts and in the age of the great Ac Milan side and the Real Madrid "Galacticos" - this is achievement alone will grant him a place in the history books.
He then went to conquer England with a record breaking Chelsea side and leaving behind a team that kept Chelsea winning titles for a decade.
With Inter, besides the back to back league titles he also won them the treble - only treble of an Italian side - beating in his way to the trophy the likes of Chelsea, Pep Guardiola all mighty Barcelona and Bayern: again this achievement alone will grant him a place in the record books.
Even in his Madrid passage he won them a League title - only one of the two Real has won in 10 years - and make them competitive again in the champions league: just remember that previous to Mourinho arrival Real had just went 8 consecutive years being dumped on the last 16: the last of them with the likes of Ronaldo, Kaka, Benzema, Ramos, Marcelo and Xabi Alonso on the starting eleven.
After that in his second passage at Chelsea he still won them the league title, a cup and took them to a champions league semi final.
Now lets get to United, the job that granted him the "fraud" nick name. In his first year he won the Uefa Cup and a Cup securing United champions league football. In his second year he finished second, in front of the so called new generation top coachs Pochettino and Klopp and in his third year he was sabotaged in the pre-season with 0 backing from the board and publicly leaks about the board not acepting the names he suggest to the club: this passed the message to the players, press and Mourinho himself that he had no future at the club and set the tone for the miserable beginning of season that followed.
In short the only club Mourinho hasn´t won the league title was at United and even at United he won trophies including a european one so yeah the "fraud", like it or not, will be back managing a top clube come next summer and I would bet my house on it, will be back winning trophies again.