I don't know, I think there is room for lots of different approaches to GMing, and I do think this should be fun (not something where people feel like they are training for a big fight every session). Definitely experiment with different techniques, different approaches, but I think we can run into issues if we hold up this ideal of the perfect GM (especially when tastes are so varied: for some folks a GM like matt mercer is perfect, for others they want someone who is more interested in micromanaging the local economy or in bringing really great tactical combat to life at the table.
Maybe it is the striker in me but the idea of being thrown to the fire is one I tend to think is informative (it is also usually how things were done around here when I started----I realize this does vary by region). I like to think of GMing more like being a stand up comedian, where you only get good by doing it. There is craft to it, but 1) there are different types of comedians, and 2) to improve your craft you have to risk bombing and you need to understand what is happening when you do bomb. One technique I use is when I have a bad session I try to mentally detach myself a little, so I am not troubled by the fact that the session is going badly and instead focusing on figuring out what is going wrong---why the session is going off the rails and seeing and testing techniques to see how much they can push it back. We can have craft and technique, but the goal of all those things in martial arts, is to make them instinctual. If you are taking even a split second to think, that's too much time. In gaming there is a flow and rhythm too and I find I GM best when I am doing so naturally, without really having to think about what I am doing. Occasionally I will be very conscious of something (like "I am going to try this technique now" or "I am going to make a point of thinking about the consequences of what the party just did and how that will play out in the enemy organization").