It's not much different than with an "I'm the decider" GM in the Thompson mold, which is typical in pro sports except when the owner (or in this case Murphy) weighs in on the big decisions. A typical GM may cut a player or let one walk in free agency because he's targetting a better player or value proposition replacement who's on the bench, available in FA or from the draft board to step in. The coach may not agree with those moves from a "decider" GM. But that's typicially the way sports organizations are run--the GM picks the ingredients and the coach cooks the meal.
Now, if Gutekunst has such power now, which is just a suggestion of something to think about, and he doesn't even listen seriously to what a coach has to say about needs and personnel, that is a mistake. But if there is disagreement, the GM decides in a typical organization.
That's not what makes for an "epic team collapse." Making bad personnel decisions would do that. Besides, this may be an epic team collapse or a semi-collapse in the making already. Time will tell.
If this happens to be case, keep in mind McCarthy has one more year left on his contract. I expect him to be the coach next season. But if this team's performance declines futher into something resembling "collapse", he just might get the axe.