How many "games" there are does not necessarily reflect their popularity.
Also, many games where the MC fucks a lot of women (who are only fucking him) are not tagged harem. I'm not sure what the official rules are for the harem designation, but I meant games where the MC gets to fuck loads and loads of women and doesn't share.
If you sort by thread views the most popular games are overwhelmingly games of "harem" type. In the top 20, there are 3 which are not "all the girls love the mc and think he's a stud" harem type games. I'm not projecting anything. It's just a fact. The idea that you could tell me I'm projecting while saying that young men want to be desired and have lots of sex is pretty out there, lol.
In any case, the technical popularity of the genre wasn't the crux of my argument. Moreso that the types of games which feature a large dicked MC are indulging male fantasies. Honestly I can't speak for female protagonist games, I'm not entirely sure of the psychology behind the guys who are into that type of stuff, or what kinds of content you can find in those games.
There is a direct correlation to how much product exists to how much it's consumed.
Genre popularity can be measured by the amount of people consuming said content, so it's not a subjective measure.
While also it's a fact devs are able to conclude their projects with financing and completed projects are a direct result of projects that managed to be financed to conclusion. (Regardless of exceptions)
The crux of your argument as well is just partially correct though girls by popular belief don't exist online "girl= guy in real life" when it comes to consumerism they are by far the biggest influential consumers small example:
Your opinion may not be completely untrue since porn industry as a whole could be mainly finance by males, still don't pretend there aren't women that buy porn content.
As far as i know males are just the ones that tend to admit watching porn.
So saying
VNs are about fantasy. For young men, this fantasy is usually some form of "What if I was a super-stud and every woman just couldn't resist me and they had a visceral need for my cock several times daily?"
Is being naive, gal VNs do exist and quite a number of VNs try to target both audiences. If anything that study kinda could suggest VNs aren't for young men at all, but for older man to fantasize about being young.
And by personal experience man just need to fap, context of "what ifs" rarely matter as long as whatever appeals to them is on their minds, could be a panty shot, could be imagining his crush giving a hand, something more or even just a hot girl photo.