Perhaps so many philosophical theories of truth exist because the concept of truth is central and fundamental and because philosophers have been discussing it for such a long time. See the SEP entry on truth for a survey of various theories.
As for non-philosophers, I doubt that they're as united in their view of truth as you suggest, and I doubt that they're united around the conception of truth that you proposed: "that which is absolutely incontrovertible and not open to debate."
I've met many non-philosophers who claim that both sides in a debate can have the true answer to the precise issue being debated: my side of the debate can be true (for me), while your side can be true (for you). I don't accept their claim, but it certainly seems to be popular.
And given how strange human beings often are, few if any statements are going to be "absolutely incontrovertible" if that means "beyond any possible controversy." If, instead, it means "not rationally deniable," then the controversy will simply shift to who counts as rational.
I think philosophical theories of truth are meant to be about the concept(s) of truth used by ordinary people: there isn't an exclusively philosophical concept of truth. Some philosophers say that philosophical controversy and confusion about truth result from trying to theorize about truth as if the concept were deep or complex, when in fact it's neither deep nor complex (see section 5 of the SEP entry linked to above). I favor that view, although I recognize that it too is controversial!