This summer Jose Mourinho decided to let him leave on a temporary basis again and the Belgian wideman linked up with former boss Moyes at Sunderland.
Speaking to The Times about the recent departures of youth team products Paddy McNair, Tyler Blackett, Donald Love and Will Keane, Butt said: "They're really good lads and will have a good life, nice houses but they weren't at the level for United.
"It doesn't hurt me as much as, say, if Adnan Januzaj went and never came back.
"He's got the level to play for United and win leagues and Champions Leagues."
However, Class of 92 hero Butt did point to one area that his fellow academy graduate could improve upon.
"Maybe he's not been as dedicated, a case of too much too soon, a millionaire now," he added.