Are any answered questions on Meta valid if Jeff, Joel, Moderator X don't answer them?
For example: Gaming the system with spam flags
plus 100s of others
Of course. Plenty of questions are factual: "How do I do such and such?" (e.g. Is it possible to move questions between stackoverflow and serverfault?). There's no need for mods to spend time on these.
It's all about delegation.
The Meta community at large has enough knowledge to solve 90% of the issues that end up here, so there's no need for the small number of moderators to give answers to all the questions. (Notable exceptions include bugs that are actually bugs, and feature requests that ultimately get implemented by the development team.)
A moderator's function on the site(s) is to facilitate the discussions, not necessarily to always be involved in them (although that is their own personal choice).
(I should point out that if a mod chooses to not answer this question, I think that gives you a pretty good answer in itself.)
They can be valid. I always vote up things that are correct here. In general if you see an answer with a lot of votes that isn't on a [discussion] question, that is because it is a valid, correct answer to the question.
Gaming the system with spam flags is a
[discussion] question. "The Team" is not required to participate in such questions. However, I am quite sure they do read them, as they are tantamount to free market research.
If you want "The Team" to participate in your questions, flag them with
[feature-request] (if appropriate).