Some analytics folks are finding that QBs that throw the fewest INTs have fewer wins because they are more risk adverse. So there's some evidence that a bit of risk-taking (or certain level of confidence, maybe?) is needed for a QB to win the maximum number of games.
Purdy certainly takes some risks, throwing balls up for grabs. Hard to know if he's throwing "too many," costing us games, or throwing enough to maximize our wins. But based on the fact we're seeing some if the best football ever played in JTS, I don't think you can automatically say he is taking "too many" risks.