In my experience so far he is allowed to get away with anything his cult base will allow. Meaning he often acts illegally and/or against protocol, the damage is done, and then maybe, just maybe, the legal or democratic systems might react.

I agree with you that it seems like his main problem is that he may be moving too fast. He seems to have decided that he must move quickly, probably due to the inherent limitations of the election cycles and timing in the US. He has to make enough change prior to midterms, and prior to the next election, to lock in his power. If you consider his main motivation to be holding onto power, then everything seems to make sense. But in this case the American election cycles and timing, midterms and presidential elections, may actually be a saving grace, because he needs to make quick changes but if he moves too quickly he will provoke too much resistance. And another thing about Trump is that he is remarkably stupid when it comes to just about anything other than branding, so he may be unable to walk the fine line between change too fast and change too slow. And it may even be the case that with the American system set up as it is, that line doesn’t really exist.