Yes, but...

The bit in parentheses (taking into account intensity) is the important bit. Trained endurance athletes run, or ride, or whatever for many hours despite it being impossible for them to ingest calories nearly as fast as they are burning them. They do this by operating nearly all the time at a level well below their aerobic threshold, so they use up only enough glycogen to allow them to burn fat (fat burning in a carbohydrate flame, all that stuff). As a result it may be perfectly possible for them to ride/run for three or four times the two hour limit without additional food because they are eking out their glycogen reserves in a miserly fashion.

Now, I am no great athlete but I have spent a long time on the bike in the last decade, and it is routine for me to ride more than three hours on just water. In fact, my most frequent route is just about three hours long and I no longer bother to take any food when riding it, because I know it will come back uneaten. I've never done the "bonk" experiment -I haven't bonked since I was in my twenties - but at endurance pace, with heart rate in zones one and two, I'd be very surprised if my performance deteriorated through lack of food in less than four hours.