Seriously, fans ask the wrong question, “Is he worth that much?”
The market for starting QBs who are not on rookie contracts and are not just holding the spot as a bridge to the eventual starter they hope to find changes every year and is seldom based on what a guy is worth.
38-40 million per year now is at or near the top, but in 2-3 years as the new crop of young, successful starting QBs get signed to extensions or second contracts, it is unlikely to even be in the top 10.
The real questions that should be asked are, “Can we win with this QB if we improve the defense?” and “Is a better QB option available to us?”