Trump doesn't care about keeping his job or doing his job and he effectively can't be fired (which is rare for most positions). If you don't care about those kinds of ramifications, then you don't need to defend your slip-ups. He really is an atypical case here.
Not in my experience.
I France we have politicians lying, cheating and even being condemned coming back all the time.
Are you saying though, that France has not seen politicians and other positions of authority say less of substance than in past decades? That they're not watching their tongues any more than they used to? That errant comments aren't taken out of context by the public and used to vilify the person who said it? Well, more power to you; the rest of us should be so lucky - all over the anglo world, this pattern has been noted, rising with the 24-hour news cycle (which rewards 'gotcha!' journalism).
I think Trump is proving you wrong.
But I get your point, the risk is really because a few people are idiots with too much powers to break things.
We see the same things with the medical personal: they get very cautious and conservative because they are held accountable when something goes wrong, whether it's their fault or not.
But then forbidding idiots to have power would not be very democratic wouldn't it ?