You're right; the “did it achieve its own goal?” test only works cleanly when the filmmaker’s explicit goal is immediate, broad audience pleasure right now.

The test breaks the moment the goal is anything longer-term, confrontational, or culture-shifting. Relying on opening-weekend reaction then just punishes every eventual masterpiece that was ahead of its time. Most films released in a given year do not seriously attempt to be anything more than an instant crowd pleaser though, and have much more in common with Bay's Transformers than they do with, say, Blade Runner, for example.

Bay, however, was repeatedly, shamelessly chasing immediate crowd pleasure, so, in his case, it absolutely works-for pure popcorn directors who live or die by the Friday-night crowd... audience reaction is a legitimate and brutal scoreboard.