Why don't questions get that much upvote love?

I'm often noticing that some questions get 0 or 1 upvote and 4 or 5 answers, with some answers scoring 3 or more upvotes.

In that case, why don't the answerers themselves upvote the question?

If it's not a good question, why does it get 5 answers when 1 answer would be enough to help the OP already?

If it's a good question, why not upvote it, possibly after having answered for the FGITW answerers, which increases question visibility, and hence answer visibility?