We found the same last year in Zakynthos (Zante). The resorts of Alykes and Alakanas were full of Greek Restaurants and Tavernas. I certainly could remember seeing anything such as McD's, not even in Zakynthos Town. I am not saying there was not, but I did not see it.
One could get an English Breakfast if they wanted to, but then, we did also see quite a few locals eating the same also. One resort we went to, was Agios Nikolas, on an island tour. Truly traditional, little tavernas and restaurants, all along the sea front, lots of little shops selling various items for the visitors.
Only one thing that got me. We went to a Greek Night, there was two to choose from. The member of the group who booked, unknowingly booked one which was run by English people, all from the north of England, (no offence to those from the north). The band were made up from their sons and daughters, and the evening finished off with British Pub songs from old. An experience, but one learns from ones mistakes., .
All in all a great time though.