No it hasn't. Wenger was awful and should have gone earlier. The fact we also have a terrible board is the reason things have gone so wrong. They are the ones who replaced Wenger with another terrible manager and doing so doesn't make it anything other than fact that Wenger was also terrible for most of his last years with us. We're paying the price for having an inept board who stuck with him for so long.Not sure what us being relegated will prove, except that those of us who were saying, don't be too quick to get rid of Wenger, were right.
Succession planning is important, and we got rid of Wenger automatically, because a minority of arrogant morons repeatedly told us, everything he did was bad. That was foolish and we are still paying the price. We should have allowed him to name his successor and groom them for the role. But everyone was so sure he was awful, that "Anything was better than Wenger".
This has been proven to be catastrophically wrong. The only thing we can do now, is try to pick up the pieces. Stop listing to the people who have steered us so wrong in the past, and try to get behind the new manager and the team. The thing we should not do is listen to more negativity, hate-filled bile about our players, and dire predictions.
If I continually served you vomit on a plate day after day and then replaced it with a plate of dogshit instead it doesn't suddenly mean the vomit was an acceptable meal all those times.
However, I'll agree with your last part. We need to get behind Arteta and give him a couple of seasons to make some noticeable improvements.

