Also, he totally sucked at getting revenge. When he finally meets up with his sworn enemy he stops to have a conversation with him.
And he didn’t even kill him, he only killed one of the guys on his list.
The whole point is that Stark is still 11 years younger in his own mind. He spent those 11 years in hell, being turned into a warhead that just flies right at whatever is in front of it. When he comes back to Earth, he does the exact same thing. He treats L.A. like an arena, and foolishly assumes all of his enemies are gonna be just like his gladiatorial opponents in the arena.
And in this way, Stark gets played. He gets the ever-loving fuck played out of him. Mason played the fuck out of him. Because he's wired to always move in a straight line at whatever is pissing him off, his enemies (and certain allies) use that against him. Repeatedly. So Mason is not just one step ahead of him; he's all the steps
ahead of him.
And no, he doesn't figure this out until he's already left behind a trail of fuck-ups.
When we pick up with the second book, Stark is beginning to learn from his fuck-ups. He starts thinking sideways. Starts using magic to bear the brunt of attacks rather than his face. He still does more reacting than planning, and he still fucks up. But now, he's aware of his flaw, and is working to correct it.
In other words, he's growing. He's learning from his mistakes.
And make no mistake, despite all the villains we see, it's Mason who is the primary black hat in this series. He's the one who's gonna do the monologuing and the outwitting. He's the guy who's gonna have plans within plans and wheels within wheels.