I was also wondering about this
We can definitely agree that tactical flexibility is an important characteristic of a manager, but if he's new, and he's trying to establish a core playing style, and approach, isn't it a good idea to try and stick to it until the players actually are able to execute it?
So far, there have been some positive stories from the official site about how they're buying into the tactics and approach, in support of Marco Silva, so maybe they're actually trying their best, it's not clicking, and he's trying to just wait for it to work. However, even from one core playing style, there should be an ability to do basics, like going ultra defensive / counter attacking to protect a lead, or trying to 'manage a game' by just sticking to shape, structure and simple passing. Those two tactics should be in the repertoire of any team.
I don't know if he's devoid of ideas, but he does already seem tired and worn out, which is not a good sign in a relatively new manager.
On the other hand, I think less importance is to coaching staff on a team, and I felt this in Martinez's 2nd and 3rd seasons, that if he had more sophisticated coaching staff, who had defensive, organisational and more fitness skills, we may have done better with his core philosophy of attacking possession play. I have often criticised managers and head coaches for blindly taking along their coaches to every job they get, just for the sake of loyalty, even if they're not appropriate. I would have, for instance, tried to keep hold of Chris Woods all those years ago, and maybe tried to get back or keep people like Steve Round, who was apparently good. Maybe Marco Silva's coaching team are not fit for purpose, and he and Brands have to actually replace some of them? It comes back to the question of Big Dunc - I'd love to know what he actually does, and is he really just a passionate cheerleader, or an excellent mentor , or a great technical coach? Before sacking the manager, we should try and hold the coaching staff responsible.