Let's face it. McVay didn't think he had enough experience and credibility to put his thumb print on the defensive side of the ball. Plus he probably didn't have many qualified candidates lining up to take the job before the 2017 season. So, he created the situation where he hires Wade and let's him operate autonomously.
Two years later, McVay clearly knows how to be a successful head coach. He will have coaches tripping over themselves to get into this organization. It will be an automatic launching point to a head coaching job. And....McVay will be running the whole show. Not that he will be getting involved into the defensive day to day.....but the future DC will need to answer to McVay on a more direct basis.
In the end, Wade will go out on his own terms. But he sees what he is doing right now isn't working. He will make the right decision and retire.