I’ve lived here over a decade with no shelving in the shower, and I finally bought an organizer! This has been a huge quality of life upgrade, it’s great having everything off the floor within reach. The shelving was super easy to install and I feel dumb tolerating the situation for so long.
I think on my side it was a combination of too tight and moisture in the drywall in my ceiling.
The other problem I had was that the shelves would keep falling. Not doing the one job it had. Not sure if it got better because the model I had the shelves were held in place by rubber/plastic gaskets.