>>56129601I wouldn't say unpopular, but moreso underappreciated or lacking specific identity. It's often compared to Rock, which has more diversity in its designs and attracts people who like fossils, gems, archaeology, etc. It's also one of the most powerful offensive typings.
What type of person specifically likes ground types though? Competitive players? A lot of those ground types are dual typing too (Lando, Zygarde, Excadrill, Gliscor, Quagsire/Clodsire, Gastrodon, I could go on) that use their ground typing to augment them. There are exceptions like Dugtrio of course, but Dugtrio isn't necessarily good because of its ground type.
What about pure ground types? I really don't think a lot of people who are fans of things like Sandslash, Marowak, or Hippowdown JUST becuase they're ground types. There's usually more to them.