I think he was scapegoated. They invested heavily in that offense this past season and the payoff wasn't there due to several different reasons but mostly due to injuries throughout the year to their skilled players.
That doesn't give any explanation to the amount of pressure that Stroud faced constantly nearly every game. We're not talking about him holding the ball for 3+ seconds waiting for WR's to get open. We're talking the ball is snapped and someone is already pressuring Stroud.
And nothing changed at all in scheme or even much in play calling to mitigate that all season long which is quite literally one of the defining jobs of an offensive coordinator.