The rumor that shuttled around a while is that the original script stayed very close to the TV show. The people who developed the film were huge Avengers fans that spent years trying to bring this to the screen and saw it as an art house action movie. When Warner's realized that they didn't have a big budget summer film for 1998,they rushed production on The Avengers, threw a lot of money at it, and more or less told the producers they wanted a big hit. Needless to say, pandering to the masses and doing good "Avengers" are incompatible, which the test audiences more or less told the studio execs during test screenings by not liking it at all and getting confused (though I am hard pressed to see how they were any more confused than I ended up) . Unfortunately, take out the sublime strangeness and the film falls apart and makes little sense. Apparently, the studio thought they could rush this out on name power and no real story and maybe make a little money, which is exactly how much they made.