Why does hunger have a much more drastic effect in cycling than in other endurance activities?
The short answer is that it is purely down to your individual training level and mechanical efficiency in each of these disciplines.

Bonking is a result of fully depleting your glycogen stores.  Once this occurs, your body's only source of fuel to power your exercise is to metabolise fat.  This does not change regardless of what activity you are performing.

However, your state of training and efficiency can impact how long your remaining glycogen stores can last.

As an example, consider the case where an athlete is significantly less trained at running, than cycling.  In this case the perceived effort level may be the same, but in fact, when running, the muscles are generating less power, hence requiring less fuel, and allowing them to last longer before bonking.