Could you explain a little bit why you see DMing this way? I realize that I'm not quite getting it. (And your view isn't unique - others have expressed a similar view.) So help me get past these hurdles.
First look at our track record as a hobby. There are SO MANY mediocre DMs out there. I've gamed all over the world with dozens of DMs. Lovely people, earnest, trying really hard, eager to have fun and have a great experience, but generally just not at all versed in how to run a table. So...if it were "easy" why do things go bad so often?
Second, why would DMing be different than any other entertainment skill or art, where people learn their craft from others, often in a structured way, and then they go and express their own style? Why would learning your craft as a DM preclude inidivudal styles or expression?
Let me say that I think part of the problem here is that DMing has all too often been conflated with adventure design. Guys spend weeks creating an awesome adventure, full of really well designed encounters, detailed stat blocks, cool monsters. Then they spend very, very little time thinking about how to present this in colorful, dynamic, engaging, interactive ways.
They think, as you suggest, that that part of the gaming experience should be 'easy' or 'intuitive.' And when things go wrong, they blame the group dynamic or their players, or they just shrug and say, "That's what RPGs are sometimes like." And sure, sometimes that's true.
But since I've been actively trying to learn the craft in a more deliberate way (all the advice and suggestions above are awesome, btw), I've found that in many instances I'm far more able to salvage and improve my games. And I'm far more conscious of why games are going wrong when they do go wrong.
I'm not looking for ideal games. But if half of Pathfinder DMs could be better equipped with behind-the-screen skills, that would change and improve the gaming experience for a lot of the community.