While it's true that various media outlets have reported that Trump is prone to skip national security briefings and dozes off in meetings, he's hardly the first president known to have done so. Ronald Reagan did the same back in the day. Reagan was easily bored with details and preferred the simple version and the "big picture" in his decision-making.
And if Trump has already decided on a policy or direction he's going to take, why let other people endlessly waste his time trying to change his mind? For instance, he already decided early this year to pull out of Syria but allowed Mattis and others to sway him and delay the withdrawal. Unless he puts his foot down at some point over the protests and threats of resignation from his advisors, they will keep making him do what he and his constituents don't want to do.
The Washington political establishment, which includes Congress and the Pentagon and entrenched politicians in both parties, has become the proverbial "tail that wags the dog." There are no compelling reasons for the US to maintain a large military presence in the ME, yet because we've been there for so long, it's becoming harder and harder to leave because bureaucratic inertia had set in. Politicians and bureaucrats have turfs, departments and budgets to protect.
The resignation of the so-called Anti-ISIS point man, Brett McGurk, is a prime example. His resignation "in protest" is portrayed by the media as if it's in defiance of Trump, when the reality is that, by ordering the troop withdrawal from Syria, he was effectively fired because his job description and raison d'etre as liason to the various groups fighting the remnants of ISIS no longer exist, which means if he didn't resign we're paying the salary of a lame duck.
Trump was elected to buck the Establishment and drain the swamp, and that's exactly what he's trying to do even if he's becoming increasingly all alone and the swamp eventually ends up draining him.