Yeah, the explanation of "why so few male characters" is because of the plot dynamics of a typical visual novel. Basically you have your hero (self insert), a side-kick, and a number of girls. The choices in the game involve which of the girls you interact with. Since you're seeing everything through the eyes of that one main guy, the format doesn't make sense for their to be independent other guys with their own independent plotlines going on. The male side-kick is generally comic relief and an info-dump type character, so he doesn't get his own storyline.
There are few dudes to talk to, because, frankly, that would be gay, and there are separate games for that
The other issue comes from how difficult it is to adapt a non-linear branching story into a single linear narrative. In e.g. Clannad, you can end up with any of the characters. But in the adaptation, that boils down to only one. So what they do is pick a girl to run with, then one by one skim over each other girl's back-story/life-problems, but minus the dating aspect, so they have to exclude a lot of the emotional material. They then finish with the main heroine's story arc. Which means the arc with the biggest impact comes
last. Clannad is especially notable for this, since the last 8 or so episodes out of 50 is where 90% of the payoff is.