Pearce and his dejected squad flew home yesterday after Sunday's 2-1 defeat by the Czech Republic sealed their early exit following bore draws with Spain and Ukraine.
And ex-Manchester City star Mills said: "Those youngsters were fearful. They seemed too aware they were under scrutiny.
"None of those players had the confidence to play and get England through.
"Nobody on the pitch stood up and said 'This isn't going well, I'm going to change it'.
"That's because academies are creating robotic players who have had everything done for them from the age of nine. They can't think for themselves.
"And holing them up in a posh hotel means the gap between them and reality is widening."