I have been thinking about it more, and there is actually a bandwidth system hidden inside Steemit, but I think it is too generous, I have never seen it low enough to stop my activity. It should, really, and I should see it. Have a look at this:

Don't you think that bar should be in the interface at the top to tell me how much I have left? You can see, because I have a small account, that I have consumed quite a bit of my bandwidth. I am looking at this again, and I think it simply needs to be exposed, and some proper user testing done to see what real humans actually need in terms of bandwidth, because bots can use far more than this.