I can completely understand that you want this. I only shared my creations once and removed my builds after a little while. I don’t like it if other player uses my builds, but not because of stealing, it … just don’t feel right for me.
I don’t mind if a user recreates the exact same building, I have also done this too, specially with houses which used heavy move objects. I liked the basic shell but not the things which as placed there.
As @xochiquetzl_xkvn says is not the single user which makes problems but if you have many users you need to make sure you have enough space to save all these things. Sims4 have over 10 million active players, so you need make sure you have at least enough space for all these players. Yeah... EA is huge and have much money but they money don’t came because of kindness. You want a service, a private gallery so you need to prove EA that they got more money if they give you this option. I think it would be nice if EA Play would get an addition feature of a private gallery if you were a subscribe there. (Specially most simmers don’t have any interest in any other games as sims)
I think it's cool if people use my builds or Sims, but I understand that not everyone feels that way! It's like published authors and fanfic, in a way: some like fanfic (and may even find it flattering) and others hate fanfic and hate the idea of other people playing with their characters. This is all personal preference and both opinions are valid.
