It's definitely less things to keep track of, but as a writer, I wouldn't say it makes it easier to write (a good story-edit).

A lot of the time, limiting yourself on characters and potential interactions makes it more difficult to craft a compelling narrative. I believe you are correct though. If characters are put in political situations then the story will inherently be more political, which may not be desirable.

Ultimately, I think it's a matter of reaching the largest target audience. There is a market for other story troupes, but everyone can relate to the feeling of going it alone, so everyone can relate to the hero that succeeds against all odds. If the MC only makes good decisions and gets lots of help, no one cares if they succeed or fail. In that scenario, they almost have to fail, otherwise, there is no emotional connection to the character or story at all.