This came out of a discussion I had with my father yesterday, where he mentioned a skill-focused / noncombat session he played in where one player had a strictly combat-focused "damage monster" character, and was subsequently bored. It got me asking the question "why do we often see characters built to focus solely on combat, but rarely see characters built to solely focus on noncombat capabilities?" In some sense this is part of the OSR's Thief Problem and maybe an issue with ACKS' Venturer, so it does sort of matter.
The naive answer is "combat is the biggest portion of the rules, and most options during character creation and advancement focus on combat", ie "the rules made us do it." There is some truth in this, but as an explanation it is incomplete. It begs the question, "Why are the rules this way?"
A more complete explanation, I think, follows from risk aversion and what is at stake during combat vs non-combat challenges. In combat, if you fail you are likely to die. Your only other remedies are retreat (often infeasible) and surrender / trust in the mercy of your foes (also often inapplicable, as with unintelligent monsters, and probably quite costly even with merciful intelligent foes). The rules for combat are detailed precisely because of what is at stake, and players build combat-monster characters in order to avoid dying ignominously.
By comparison, non-combat encounters are likely to feature a wide variety of possible outcomes, and are less often immediately lethal on failure (these do happen, but the proportion of potentially-lethal combats much outweighs the proportion of potentially-lethal noncombats). This is why noncombat gets both briefer treatment in the rules and less attention from players; if a non-combat is going poorly, one can often "retreat" from it more effectively than one could a combat, and seek another way around. Couldn't pick the lock? Time to bring out a hammer. Couldn't bribe the guard? Time to find some blackmail fodder, or a back door, or any number of other approaches. But once the swords come out, somebody's going to end up under a shroud, and you'd rather it weren't you.