>>27114106They probably thought that it would be unfair for balance, as if you know a pokemon can have levitate, you will never use a ground move on it. Therefore they don't want to give a pokemon a second ability it could benefit from while indirectly benefiting from levitate by the opponent never using ground moves.
Bronzong is one of the only exceptions, as it kind of had a gimmick where it only had two weaknesses, with two abilities to mitigate both.
>>27114299HA duskull as well is frisk, which doesn't really make it problematic because it is an announced abilitiy
