The answer depends on what you expect users to do with the model from the 3D Warehouse. As I wrote, low-poly models are excellent for showing secondary elements in a model (that is, items that aren’t the main subject of the model but show details of placement and give a general impression) without causing SketchUp to slow down. That is often what users really wanted. In contrast, some of your competitors have posted models that have hundreds of thousands of edges for high realism, but really bog SketchUp down.
But if the users intend to attempt a photo-realistic render or closeups of the shower, the model will look somewhat “edgy”. It could indeed be a large amount of work to convert a lot of model files to more detail. It generally requires judgement about what matters and how good is good enough, which does not lend itself to automation.