To be fair most people don't care about or know things until they hit public consciousness. Which is why having videos on multiple channels spreading the visibility is great. The tsukihime ip has been dead for many years and now they are attempting to revive it. Every thing is niche until it isn't.
Demon slayer is the most recent example as we can specifically point to the anime being the primary driver of growth. Tsukihime one day could just as easily ascend with enough eyes on it. Of course right now visual novels are inherently a niche medium.