Ronaldo, who left United to join Real Madrid in 2009, rejoined the Old Trafford club from Juventus in August 2021.
However, he had his contract terminated in November 2022 after he criticised the club and said he had “no respect” for then manager Erik ten Hag in a previous interview with Morgan.
In his latest interview with the broadcaster, the 40-year-old said: “I’m sad, because the club is one of the most important clubs in the world and a club that I still have in my heart.
“They don’t have a structure. I hope that changes in the present and future, because the potential of the club is amazing.
“They are not on a good path. And it’s not only about the coach and players, in my opinion… He [manager Ruben Amorim] is doing his best. What are you going to do? Miracles are impossible.”
Amorim, who took charge of United in November 2024, led the club to last season’s Europa League final but they missed out on the trophy – and qualification for this season’s Champions League – as they lost to Tottenham.
They finished 15th in Premier League, their worst performance since the 1973-74 campaign in which they were relegated from the top flight.
They spent more than £200m in the summer but started this season slowly – including being knocked out of the Carabao Cup by League Two side Grimsby Town.
Amorim appeared to be under pressure, but United co-owner Sir Jim Ratcliffe said the Portuguese needed three years to prove he is a “great” coach.
In an interview in March, Ratcliffe said the club had “not performed at the level that has been expected” since the departure of Sir Alex Ferguson as manager at the end of the 2012-2013 season, adding that some United players were “not good enough” and some were “overpaid”.
Recently, United have shown an improvement in form, winning three of their past four league games – including a victory at Liverpool – and are eighth in the table.