I think that's simplifying it, really... It is maddening, I'll give you that - but just because, well, it sucks to see a bad offense haha.
Before a CoVID policy was in place, we had absolutely no cap space - especially after franchising Thuney (which was a BIG move to make on O - we literally allotted most of our cap to offense this off-season).
By the time there was a policy, most of the worthwhile offensive playmakers had been picked. I wish there was a list so I could confirm this, but if I remember correctly there wasn't any FA worthwhile, or they were too expensive (still) and what's left to explore are trades. Which ties back to the whole "welp, teams know we need it, so they have all the leverage." I don't think Bill wants another Sanu situation.
Furthermore, there is absolutely no guarantee of a season finishing. Long term, that makes it difficult to pull a trade and feel good about it. Before the Cam signing, this was a rebuilding year and I'd say a decent chunk of this board just accepted it. It was bound to happen. And it made sense that not a lot of moves were made when there was little to do with the resources available.
Cam coming in was only because he was so damn cheap, like... Absurdly cheap for what his ceiling is. And contrary to your "style of play" issue, his strengths work with how the offense is currently built, far better than Brady. (Obviously, in no way am I saying Cam is better than Brady as a QB. Brady is the literal best of all time. But not in this offense.)
Whether we like it or not, in terms of the offseason market and the context behind our cap, Bill made the most logical and sound decisions for the team with the long-term in mind. Cam immediately made what little potency we had on offense a decent amount more potent.