I treat all encounters as "encounters", it doesn't matter to me which pillar it is. But then again, I also grant XP for role-playing.
There is certainly "more to combat" because that is the pillar that has the most support when it comes to rules, etc.
However, if you mean that more encounters are combat than exploration or social, that is often the case IME, but I don't care about that balance personally.
I agree to a point, but it depends on the encounter and how casters also handle it. Are casters using spells? If so, then martials need encounters to handle via their features (e.g. fighting or whatever). However, if casters are handling encounters through skills, then martials can do the same.
For example, in our session tonight, I had an exploration encounter (handled via skills and saves), a combat encounter, and then three social encounters (handled via skills and role-play).
Ultimately, I don't care at all about the number of encounters during an "adventuring day". IMO the concept is ludicrous. The narrative drives the number of encounters and when PCs can get in a rest. Since players never know when an encounter will take place or how many there might be before they can rest, they have to play conservatively much of the time. If they nova too much, they'll get burned eventually. It is a balancing act, really, but as long as it is dictated by the story, the balance is self-enforced IME.