As for the wearing out that did happen, aircraft have a finite life and the pressure of combat adds significantly to the wear and tear. Some planes would have accumulated damage over the weeks to make them not fit for combat, some will have been overstressed in the heat of battle or suffered structural damage in heavy landings. Also it should be remembered that most of the Me109 aircraft had been fighting for months in the battle for France without any let up in the field. Whereas the vast majority of the RAF aircraft had only started combat from around Dunkirk and were mainly operating from home bases with all the infrastructure support that helps servicability.
There was also the pressure of pilots. It is clear from the link that Kurfurst gave us that the fall in the servicable Me109's was significant and serious, but that the fall in pilots ready for combat was even worse. In September if you only have 676 pilots ready for action, it doesn't matter if you have 717, 850, 950 or 2000 servicable aircraft, you only have 676 pilots to fly them.