@Flying Dice As for the sales charts figures, I think you have a good argument if limited to DVDs and other merch. However, i'd still argue that manga sales are a good measure. Manga are a fairly standardized commodity in terms of production and localization costs, pricing, and amount of content per unit. You can get pretty much any genre in America, however shonen battles and boobs are the big market leaders. If the cause is just that they translate too many shonen & harem ones and not enough of the other ones, then in fact that should bias the market the other way: sales spread out thinly across the shonen market with high sales for the few seinen ones that you can get, because of unmet demand.
Except that a lot more "niche" adult-oriented (non-pornographic) series make it across as manga than as anime. Like all of the historical dramas produced by Kazuo Koike and Goseki Kojima, you see those pretty regularly anywhere that doesn't exclusively cater to the teen demographic; if you read comments and reviews you'll find people talking about how they needed their reading glasses because of the small size &c. shit. That is, concerns of an adult audience that's on the far side of middle age.
It's a pretty natural thing, too, given that a trial import of the first few volumes of a manga is a much lower risk than making an anime adaption or translating it. There's also the aspect that the overall cost of purchasing an entire series is much more expensive with manga than anime-a short series of anime is about one season, $20-30ish. A short manga series is ~10 volumes, or ~$80 at $8 per. So there's more incentive to read scanlations than watch fansubs (even without considering that scanlations don't have the same quality loss issue as video or that translating text on static images is easier than the limited video editing necessary for subs), but at the same time the cost of entry into a manga is much lower once you've decided to buy it, because the lowest degree of per-unit cost is markedly smaller (one volume vs. one season).
I'll take this from a certain popular scanlation site's "most popular" list. That is, the most-viewed series.
The top 30: Very heavily combat/adventure-shonen. Not the battle-harem bullshit, just the Big Three, Hunter X Hunter, AoT, Gintama, Assassination Classroom, &c. A couple shonen school life stories. A couple shonen romcoms. Two shoujo romance/SoL stories. Two seinen (OPM and a seinen mystery/school life series). Only
two with the 'ecchi' tag. Only
one with the 'harem' tag, and that was Hayate the Combat Butler.
31-60: Some seinen (Berserk, Gantz, &c.). Quite a bit of shoujo romance with one or two smutty ones. A couple more shonen action series. A sports series. One shonen romance. A josei romcom. Two of the better-known harem-ecchi trash (R+V II, Highschool DxD).
61-90: A whole lot more shoujo romances and romcoms of various sorts, with one or two shonen romances thrown in. A couple sports series. A mystery series. Three trashy ecchi series, one shoujo harem series (and if anyone thinks those don't exist, you
really don't pay attention).
91-120: A bunch more shoujo romances. A couple sports series, a shonen romance, a couple shonen action series. A gen-audiences mystery/romance. A non-romance shoujo series. A yaoi romance. Two trashy ecchi/harem series. Plus Negima, but it's a disservice to just call that haremtrash and walk away.
121-150: A romance/mystery. A bunch more shoujo romances, mostly romcoms. A couple yaoi romances. A seinen action series. A josei romance/ecchi series and a seinen romance/ecchi series. A sci-fi drama. A comedy. A dark comedy. Two ecchi/harem trash series.
For the record, it's one of the most popular and long-standing scanlation sites, and doesn't take down licensed series. The overwhelming bulk of the most popular 150 are shoujo romances of various sorts, though the top places are held by the big-name long-running shonen adventures (likely because those cater to mixed demographics a bit better than shoujo romances). Out of that 150, only ~12-15 are harem/ecchi trash, and few of those are near the top of the list.
What this really says is that the most popular stuff are series which are fairly straightforward, targeted at the 8-16 brackets, but which (largely because of differences in cultural opinions as to what's acceptable material for children) have enough mature themes and content to appeal to mass market audiences of late teens and 20-30 somethings as basic entertainment that doesn't take much thought.
It
also seems to confirm that the bulk of the battle-harem softcore porn bullshit stems from the LN market, and is expressly made to appeal to otaku types-the more general LCD appeal is already saturated by shonen action and shoujo romance. Overlap in popularity is mostly, I suspect, because haremshit series superficially resemble shonen action series and the primary target audience of males 12-16 aren't going to be turned away by T&A or shitty marty stu author/audience insert characters.
So no, manga is not a good indicator of the popularity of haremshit series. It's quite the opposite, very few manga of that stripe are popular, and those that are are ones where it's a side dish to other elements, as with titles like Negima and Highschool DxD. I mean, we've already talked about this, how most haremshit anime are LN/WN adaptions.