The single hardest part of running a self hosted instance is the initial setup. There’s very little maintenance involved if you set it up right. Storage and bandwidth are going to be directly related to what you sub to. If it’s all images and videos sure. I’m sitting at about 14GB storage right now and my bw is pretty modest.
I can certainly see people getting bored with it and abandoning their servers tho. But I doubt it’s the upkeep.