My line of thought is that yes the end goal is shareholder value/money, but the method varies. You can go for quality or quantity, or for long vs short term profits. And those steps in-between matter.

In this case with WB and Superman the amount of money an occasional Superman movie can make is not enough, they want that sweet franchise model. But you can't just will that into place, as they've demonstrated with their failure to do so so far.

There has to be some substance at the start before you can roll out even lesser IP and make bank like marvel. Which is why in this instance they probably don't care as much about the profit from this movie, but try to optimize it more for audience and critic appeal.