Like anything, free hosting will require a lot of work. It's not a get rich scheme people believe it to be. There are many ways to limit abusive users, one way is to charge a one-time fee of $1 to get the free hosting. Majority of abusers won't even bother paying the $1 as it's too much work and you lose a $1. But, someone seriously looking for a quality free hosting company will pay the one-time fee.
You are not talking about the subject, I am talking about FREE webhosting.
I've used to do free hosting way, and I mean way back in the day and it was decent in earnings. I made people pay by posting in a forum and that is how I started my paid hosting company.
Please, I am not a believer, for sure you had other resources. More users you have you need more resources I mean money, time etc. Most of the free web hosting services are using garbage platforms, run buy "kids", not real pro. They don't now nothing about security that's why we have spam and abusers. In my opinion, if free webhosting doesn't exist, of free emails Internet will be more safe.
I did security (webservers) for more than 15 years (the time when wasn't cPanel) and believe me it is enough 2 minutes to make all your work of 15+ years equal with 0. Security of a server is not a joke, or just in Windows clicking next, next and finish, and is done. But it will be a lot of action in free webhosting , that was the part that I liked it.
I never really had a problem with abusive users because people had to pay something in order to use the service.
I don't believe you. (I lived 18 years in communism, I learned to trust no one

).
But, for a free host to even begin to make some cash you will need a few hundred free clients.
Not true again, I ran 8000+ users and I did like a few hundreds / month, the work was crazy, not worth it ....
Do not do FREE webhosting, it is a waste of time and money.
Regards