I just saw that my previous thread was closed, because the servers may crash when posts are longer than 200 posts.
Anyway this is the old thread http://www.gamesas.com/topic/1554816-the-minutemen-are-unrealistic-spoilers/
I have argued that the Minutemen wouldn't be able to defeat the BoS. People have argued that the BoS knights and Vertibirds is pretty weak in the game, but they are only weak because the game demands it and that doesn't change the fact the they aren't supposed to be weak. Just look at the facts: The BoS exists for over hundreds years, they have are trained soldiers with superior armaments and air superiority.
The Minutemen are just a bunch of people with self made weapons and howitzers made out of garbage. The Minutemen consist of two kinds of people: People without training and people who were Minutemen when the Quincy Massacre happened. The Quincy Massacre only happened, because the other Minutemen refused to help, when Colonel Hollis called them. So the former Minutemen are coward backstabbers who have forsaken their comrades. They had an obligation to their comrades and the people of the common wealth and they simply refused to fulfill this obligation.
People have argued that Brotherhood Outcasts also betrayed their comrades, but they simply left, they did not abandon them during a battle. They said that it is their obligation to help man kind by finding and retrieving old tech before it is lost. While the Minutemen simply ignored any obligations they had. And the the secession of the outcasts happened 10 years ago, the Quincy Massacre happens about two weeks before the player meets Preston.
The most crucial points of the victory of the Minutemen over the BoS is that the BoS doesn't take action the Minutemen build Howitzers and that the BoS attack the castle, where currently all Minutemen are located, instead of conquering their settles and thereby draining their supply and seizing the howitzers.
The BoS is known to be paranoide and the Minutemen just demonstrated that they are capable of defeating the institute, while Preston constantly tells people how much he hates the BoS, even members of the BoS.
The BoS can use their mobility in order to conquer settlements before the Minutemen can sent reinforcement. The BoS could then use the howitzer for attacking the castle, the Minutemen had to shell this settlement with their own howitzer before the BoS use the howitzer of the settlement to destroy the castle.
The Minutemen don't defeat the BoS the player does, the Minutemen just ride along.