>>23494534
It’s more about appearances. The main villain doesn’t have to be all that proactive, but you don’t want to see them sitting in the same chair for 20+ episodes.
Ark is a good example of a really passive actor that still was intimidating when he needed to be.

Back in Showa, RX had a similar set up as the Stomach Family, but General Jark still got some respect he constantly had an eye on his lackeys efforts and served punishments regularly. Also, the episode the finally stepped into the fray, he killed off major characters.