I didn't mean the content we are getting. I kinda put it wrong with "losing steam". ZUN is still going strong, stronger than I expected from him as a father of two now. I mean, we just got a new game released in August, two new mangas are now going on... its great that Touhou is still putting out content after so much time without having lost any of its charm.I personally don't think Touhou's lost its steam at all. Unless you mean in terms of popularity, in which case yeah I agree, though I wouldn't say that's a bad thing since most of the people who jumped ship were people who bandwagonned off of old memes and then jumped to the next hot thing with cute girls (KanColle, the sleu of gacha games, etc). I'd argue in terms of series quality Touhou's not dipped at all. Touhou 16 had a very fun that felt reminiscent of the earlier Touhou titles, Antimony of Common Flowers was genuinely fun to play, the gimmick was sweet, and the new additions to the roster were great, especially Shion and Jo'on being characters chock full of personality and with a banging theme. I personally feel Touhou 17 is one of the best games in the series, both in terms of its fantastic OST and in terms of its story and cast, the new setting of Hell and the conflict in it with its incredibly memorable characters made it a great entry in the series and shows that ZUN's not lost his luster for the series at all imo.
Besides, ZUN's said before in an interview that even if Touhou loses it's popularity, he will still continue to make the games because making the series is his passion. I have nothing but immense respect for that attitude and how even when the series was at the peak of it's popularity he didn't once choose to sell-out. I doubt he'll do so in the future either since he seems to be firm with the idea that fan-related content is just fan-related content and that whatever he decides to do with the series will be from his own decisions instead of caving into fan demand, which I thoroughly respect.
I meant the popularity. Given, the only empirical data I know of are the yearly popularity polls in Japan, of which the number of votes is steadily decreasing over the years. It doesn't mean anything, I should know that. Still irks me that fewer are people are part of the community, even if those weren't fully "in".