I don't disagree, but IMO that's where the movie crosses the threshold from art to mindless entertainment. The execs are more often than not people who don't have years or decades of experience crafting movies, just funding them. They don't know what works or not. Same with the target focus group as ironic as it may sound.

The execs may know that old-movie was a flop, but not why it was a flop, and are afraid that new-movie becomes a flop too. That's understandable, but the only way to prevent this is to hire the right people with loads of experience who can say exactly what went wrong in flops and successes and apply that knowledge to new-movie. Focus groups are just too narrow to allow that to happen, so even if they identify a fault (not unlikely) they apply the wrong solution. Maybe they needed better dialogue to emphasise the twist? Lighting changes to help guide the viewer's feelings? Instead they scrapped it at the detriment of the artistic vision which more often than not will come back to bite them in the profits anyway (like now when they are thinking of making a sequel to a movie where the main protagonist dies in the theatrical version and have to say "forget that, it isn't canon").

But that of course puts a huge burden on getting a good team with good experience. Mix of new people with new ideas and old people with wisdom. And most importantly, people who are open to be challenged by the other people's expertise. That usually doesn't happen if "profits!" is the first and last thought on your mind as an exec.