I´m just going to concentrate on the bold here:
How has he not be given a chance? He had eight months, two transfer windows and around 40 games to make an impression. This is more than enough to judge him as a manager.
Your results are dissapointing to say it kindly. Your set up is predictable and static. Your overall approach is way too cautios and negative, which led you to lose your once famous mentality edge over other teams. The squad is devoid of confidence. He received over 70 Mil. € (I have seen whole successful squads built on that kind of money), but the actual problems in the squad are not solved. You still lack an creative midfielder to make your game less reliant on width and crossing and you still have no proper back ups for both fullback positions, which is mindblowing for a team with a 200+Mil.€ wage roll.
The worst and most worrying thing is that they are no signs of development and progression. Why in the world would any board on the planet give a guy a huge amount of money to build "his team" when he can´t handle the current one, which is capable of way more than it shows right now? Rebuilding a squad is not some previlidge of a coach, it is something that should be earned by making the given teams perform on an acceptable level. Any great architect (Guardiola, Klopp, Simeone, etc.) had to first and foremost show that they can make the most of the initial teams until they were trusted with investions.
Giving Moyes a huge amount of money to build "his team" could lay some serious damage on the club, because it is likely to turn out to be a waste of money and time.