There is a point where the marketing no longer matters.
In my little world of theatre, my experience has been that once the show is reviewed by the press the impact of direct marketing is reduced. By that time the public opinion on the show has been formed. So if you were to look at my marketing budget you would see heavy investments in the weeks before the show. That's the time that opinion can be shaped by marketing. Once the show is up and running, a lot of things are out of our hands.
Of course it isn't a popular thing for marketers to say that there are things that can't be controlled. People want to see marketing as a magic pill that always produces outcomes. That isn't the case.
A key part of smart marketing is knowing when it is time to stop marketing one thing and invest your time, money and energy into the next thing.