Robin Huw Bowen, Andrew Lawrence-King, and Ben Brown spring to mind. I'm learning to play the cross-strung baroque Spanish harp, and I know there are other players of chromatic harps of various kinds on this list. It's useful enough in the repertoire I want to play that I don't regret my decision to use that tuning.
People take up brass, woodwinds and violins despite their inability to play polyphony.
Lutenists, guitarists, drummers, and singers all persevere despite their instruments' technical limitations. Twelve-tone music, jazz, and other highly chromatic idioms remain specialized corners of the music world. Tonal music, based on keys and modulation, still reigns supreme, and pedal and lever harps work pretty well for that music. The big disadvantage of the single-strung chromatic harp is that makes most of what most harpists wants to play harder in order to enable them to play a small amount of additional repertoire that didn't particularly interest them in the first place. If there's a demand, there's a harp maker out there who can and will fulfill it.