He is a great manager but he does have his own way of working that includes taking the time to instill his ideas in the team and making sure they are executed to the the absolute best. And this takes time. If you know how short and far between national meetings are, you'll understand that it would be difficult for him to work as he usually wants to.
Another aspect is that, up to a certain point, in national teams you have to make do with the players you have. As far as I know, Pep always wanted to have a say in the market to buy the players he liked. That's why I said that if he really had a thing for national football, he'd go for a team with good players.
I can make you an example; in Italy we had a good experience at national level with Conte, who is very different from Pep but just as detail-obsessed, and even he only managed to stay away from club football for two seasons (one Euro) because he complained he had too little time with the team. Keep in mind that, as I said, he is different from Pep; he usually needs very little time to build a winning machine and he's very good at making do with the players he has. He should be a better profile for managing a national team.
But some managers need club football.
