QPR director of football Les Ferdinand attempted to keep the promising winger at Loftus Road, but admitted that the lure of the Premier League was too big for the player.
Ferdinand told Standard Sport: "I had a chat with Josh and his dad in May and told him that he would play for our first team quicker than Everton's.
"I made all the points about the advantages of being here at QPR and hoped it resonated with him.
"We hoped to keep hold of him, but when a Premier League club comes knocking on the door, they have the finances to make a move."