Having been called up to the national squad by Fabio Capello for the midweek friendly, Cahill had to watch from the substitutes' bench as England ran out 2-1 winners.
Coyle believes it was the perfect chance for Capello to give the 24-year-old his first run-out but is confident it will soon come and is backing Cahill to cement his place in the England set-up for the long term.
"There was an element of disappointment and frustration because we all felt, and were certainly hoping, that we would see him wear that England shirt, which he would have done with immense pride," Coyle said.
"As great as it was to have him in the squad, we all wanted to see him pulling that shirt on and it never happened.
"I'm disappointed for him because I felt it was a perfect opportunity for the whole country to see him.
"Ask any manager in the Premier League and they all know his qualities, but it would have been nice for the whole country to have seen that.
"Michael Dawson and Phil Jagielka (who both featured during the game in central defence) are terrific players and deserved a chance, but I just felt it would have been nice to include Gary within that as well.
"I have no doubts it will come. Gary Cahill is a top-class player and one that is getting better.
"Week by week, I believe he is improving and there is no doubt that he will be one of the England centre-halves for years to come."
One player who did come on as a substitute to make his England debut against Hungary was Arsenal's teenage midfielder Jack Wilshere, who enjoyed a successful loan spell with Bolton last season.
Coyle has repeatedly expressed his desire to bring the 18-year-old back for another temporary stint at the Reebok Stadium and feels it is vital Wilshere is able to play regular first-team football in the coming season as his development continues.
"It didn't surprise me how comfortable he looked on the ball and I think you saw soon after he went on with the tackle, he was determined to put his foot in," Coyle said.
"He is a brave lad in terms of taking the ball, being prepared to take kicks and even giving them out, so I have no doubts that he will be a big England player.
"It also wouldn't surprise me if (Arsenal manager) Arsene (Wenger) feels he is going to play - but the only thing I am saying is that he has to play now.
"He had six months with ourselves where he played week in, week out and he is at the stage where he has to play.
"You have to remember the quality (Arsenal) have in that midfield area and the fact that Cesc Fabregas is staying, which is a terrific boost for the Premier League but might make it more difficult for Jack.
"Ultimately it will be Arsene's decision, but we would be delighted to have him."
Coyle confirmed today that he has boosted his ranks by signing striker Tom Eaves from Oldham, another 18-year-old, who scored a hat-trick against Bolton in a recent pre-season friendly and becomes the Wanderers' fifth new arrival this summer.
"We're delighted to have him and we'll look to gradually take step upon step with him, to such a time where he is ready to challenge for a first-team place," Coyle said.
"The fact he played in that pre-season game and did very well against us just cemented what we already knew about him, and that is that he is a young player with great potential making his way in the game.
"We'd been and watched him previous to that. He played against Liverpool four days earlier and did very well. So we were very much aware of him before our friendly at Boundary Park, and we had actually started dialogue with Oldham before that match."