Another business which ran into this in its early days was NaturalMotion - they were initially building tech for realistic animated interactive porn - and they

Another business which ran into this in its early days was NaturalMotion - they were initially building tech for realistic animated interactive porn - and they got an initial round of angels (HNWIs) on that basis. Of course, they pivoted and ended up producing tech for movies and games, but porn was where they started. It's not impossible to get investors for an adult startup (far from it), but it is hard to grow, as word of mouth and so-forth doesn't work so well there, for fairly obvious reasons.