Yeah, I'd love their to be a study to work out why Frank failed so badly at Spurs, but there won't be, so we are just left with using our own intuition and some common sense.
He simply doesn't have the personality, and lacked charisma to manage a big club. It's as simple as that. He's nerdy like you say, a lovely guy, but that's just the issue, when you think of Frank you think, yeah lovely guy. But you don't think, born winner, charismatic, a leader of men.
I just don't think he really knew how to do anything than keep being a nice guy and hoping it would all work out.
The lack of discipline in the squad, and time keeping etc showed that they didn't respect Frank. Then on top of that, you have his style of play, too much time focused on stopping the opposition, and you can see why the players didn't take to him.
If you are someone like Romero, it's easy to see why you would find someone like Tudor, who has played for Juventus at the highest level, a club you also have an affinity to, much more relateable and a man to respect, than Frank.
It's just the way it is. Yeah we can think the players are idiots, but ultimately a managers job is to get the best out of the players, and get them onside and performing.