Moyes was axed by United inside the first year of a six-year deal after succeeding Sir Alex Ferguson in 2013.
Reflecting on his time at United, the Scot said: “I don’t know if I’ve ever heard anybody really come out and say it directly. I’ve had plenty of people say it to me; plenty of supporters say it to me, and plenty of journalists say it to me.
“But I think that really at the time it just probably wasn’t right and it didn’t work for different reasons. I wish it had worked.
“But it didn’t work at the time and that’s it. In a way, it’s gone now, it feels so far away in the distance.”
He continued: “I always thought when I took the job that it wouldn’t be able to be fixed quickly.
“I saw that not long after I went in that it was going to take a bit of time.
“I think also you have to remember that it was not just to do with the strength of United.
“It was to do with the strength of other teams; Manchester City, Liverpool, Chelsea and Arsenal were all incredibly strong teams. They were all rebuilding and bringing in more all the time.
“So, I think that those clubs played as big a part in it as anyone else – that their quality had risen or was rising all the time."
Sack culture
Moyes added, “The history of Manchester United was not that (one of change). Manchester United had a great culture.
“They stuck with their managers, they brought through their own academy boys. They actually had some of the best characteristics of what you would want your club to have; good values.
“Sir Alex had great values at Manchester United, and over the years those values he established needed some time to come through as well.
“It was always a club with brilliant values with an understanding about bringing their young players through and developing them in the right way.”