I don't know. I think you're just letting your extreme aversion to such scenes lead you to seeing patterns where there aren't any.
Aversion? This sequence is fine, somewhat believable and funny (mainly Adol's reaction and the pacing). I'm more worried about needless repetition in the script than one or two moments like this which aren't the focus in Ys VIII.
I really just don't see there being any conspiratory effort on Falcom's part to manipulate this nebulous "otaku" audience into buying their games.
Whether it's conspiratorial or obvious, Falcom's catering to a different audience now vs. their Windows PC days. I think otaku have always been their most profitable market, just not the main one they kept in mind when developing games. Sorcerian became a pillar for them not because everyone bought the 1987 original, but because fans kept buying and asking for more scenarios which Falcom contracted out to developers and, eventually, the fans themselves via Selected Sorcerian. (All of the extra scenarios were made mainly for PC-88, too, which indicates a platform bias. Falcom made PC-88 games up until 1992! They had PC-88 otaku and late adopters to worry about.) We're seeing a huge emphasis on Kiseki now which the Gagharv and original two Legend of Heroes games never had. There were series like Vantage Master (made for wargaming fans, otaku who bought from Koei, System Soft, and Kogado) and remakes like those for Sorcerian and Dinosaur in the early Windows days. Centering on Kiseki and using some of its elements in Ys to grab new players is a double-edged sword, but one that's paid off commercially. Tokyo Xanadu could become their cheap, reliable otaku series to ride out the end of the Vita's lifecycle for all we know.
None of this would matter if Falcom stabilizes their development schedule, expands the development team, and makes one smaller, well-priced multiplatform game every one or two years. They'd have room and reason to experiment on both Asian and Western audiences. Moving to PS4 and not relying on a concentrated Vita install base will force them to change at some level, unless NX becomes a surrogate for the Japanese Vita market and Falcom jumps to it.
and for the most part, the typical "Otaku" audience doesn't care and has never cared about Falcom games. Sort of evidenced by the series historic lack of fanart and licensed merchandise compared to games that do actively seek that audience.
Either that or the doujin works simply haven't been scanned, documented, and made available outside of interpersonal/market sale, auctions, &c. There's an odd lack of Falcom hentai relative to what other Japanese (console) developers' IPs get. Maybe the people who normally commission doujinshi neglect Falcom works in favor of others. There's plenty of works coming out for Sen no Kiseki, so the trend's changing. Falcom's licensed their IPs out to a few figurine companies in the past—promo deals meant to push sales for a game (Ys VI had a lot of this)—but it's hard to track it all down. At least you can get lotsa doujin albums with Falcom remixes on them.
I think they put in things like the Raxia scene, the Feena easter egg, the Olha bikini art, the Elena maid costume and the Yunica Schoolgirl outfit because people on the team just like that stuff.