Were he to remain at United for that long, Mourinho would have been in charge for 17 years, something he doesn't believe is possible in the increasingly pressurised and demanding world of football management.
In that sense, the 54-year-old sees Arsene Wenger at Arsenal as something of a dying breed.
Unfortunately, Mourinho's comments were sensationalised and whipped into something of a media frenzy that happily implied he would quit United sooner rather than later, which was absolutely not the point he was making when he gave the interview in question to a French broadcaster.
"The only thing that I told is true and there was not a misinterpretation of my words - I am not going to end my career at Manchester United," he clarified at a press conference (ManUtd.com).
"I was asked how is it possible in modern football that any manager is going to last 15 to 20 years in the same club. I think Arsene Wenger is the last one at Arsenal. I think it is impossible for us with everything that surrounds the job, all of the pressures that surround the job," he then explained.
"I think it is impossible to last for so long. If, in this moment, I wanted to finish my career in two, three, four or five years then I would say yes, I want to finish my career with Manchester United."
Mourinho has never held any managerial job for more than three seasons, and while he has often hinted he would like to lay down a longer legacy at some point, he sees another 15 years until retirement as being too much of an ask.
"I think I am going to be a manager for 15 more years, minimum, in the job, and I think it is impossible to stay for 17 years in the same club," he said.
"I think it is the impossible mission. Even if you want to, you can try, but I think it is impossible. Wenger is the last one. That was my answer. I don't think I am going to end my career at Manchester United. That was my answer.
"After that, some people tried to be clever, some people tried to be malicious and they said many different things. But the reality is simple. I did not sign a new contract but I am not thinking about leaving."