The Dutch goalkeeper enjoyed a fine six-year spell at Old Trafford to end his career, winning four Premier League titles, as well as featuring in three Champions League finals.
But since Sir Alex Ferguson departed, United have struggled, failing to win a title and currently languishing in the bottom half of the table under Solskjaer.
And Van der Sar has pinpointed a clear issue in the current United dressing room.
“So it’s a long way from the position where they are in now,” van der Sar told ESPN. “And of course they have changed managers a couple times now and the real progress is not seen yet, only the thing that they bought in the summer.
“They bought younger, inexperienced players with a certain desire and hunger, and not like the big names they bought the last six, seven years.
“I think for ourselves, when I came in the dressing room we had Ryan Giggs, you had [Paul] Scholes, you had [Rio] Ferdinand, [Gary] Neville and even Roy Keane at that time. So I think there’s always been strong characters.
“And I think for the last couple of years the strong characters have disappeared and [are] not making a difference anymore.”