Well, he does make the most sense in terms of potential...for getting drunk, jumping on tables and running from the police. That skill set certainly is the best "fit" in the draft, if that's what we're looking for...
Have you watched any of Rosen's games? The ones I saw last year had him continually battling from behind due the Bruins' putrid defense. He was at the mercy of the pass rush (behind a meh O-line) and had to play hero ball to give his team any hope of staying in games...
None of whom were considered "blue chip" franchise-type guys.
Johnson was a 4th round pick (#99) of the Jags who flashed enough in last two games of 1997 to fool the Bills into trading the 9th pick (plus a 4th rd) for him. I guess that's an investment, but it feels more like a panic move. Flutie was a fluke that actually worked out. Bledsoe lost his job to a kid drafted in the 6th round. Losman was another panic move.
None had the feel of a well-thought out strategy for addressing the long-term future of the team...
Over a 50-year period, Ralph so-little valued the QB position that Kelly was essentially the only blue-chip prospect they ever drafted at the position. And that was when he lucked into having him drop to the Bills at #14. Somewhere over the span of those five decades there was an opportunity to work the draft to land a true franchise guy...
I put this on Ralph to a large degree. He was just not going to be aggressive when it came to trading up for a QB. The parade of GMs that passed through his tenure took their lead from him.
Did he get more invested in the team in his later, post-SB years? Yes. But did he embrace the risk/reward of getting another franchise QB after Kelly? Nope...