My first WIP thread (which included a finished game, more or less!) had 22 total posts, and ~10 were mine. I muddled through anyway, eventually submitted it to HG, and sold over 1000 copies my first month. I obviously don’t know the secrets of harnessing forums attention but I can promise you can succeed without it.
That said, feedback is important and it looks like there were a good amount of people that expressed interest in your thread. Not sure if they all ended up flaking or whatever, but you certainly grabbed the eye of a lot of folks. Maybe try following up via PM or email? I agree with you 100% though–there’s always this ugly part of me that gets jealous when a new WIP pops up with three hundred posts, fanart, and a booming patreon or something overnight. I’m generally happy for other writers’ success but… yeah. I want attention too! We’re human! If I crack the formula, I’ll let you know 