Change My Mind

some even lack henchmen

Are you sure it's not because they monolouge?

I for sure did not spell that correctly.

some have henchmen, some have their henchmen turned sides, some have competent henchmen but not enough to overpower the protagonist, and the list goes on

Or they "remove" their henchmen after they get the power they want.

No they fail because Walt Disney thought that the bad guy should always lose and die.

It's called plot armor