I understand your reasoning, however I think you're putting way too much weight into Purdy's "late game" abilities and not enough into the rest of his abilities. NFL scouts probably aren't either considering some currently have him pegged as a top 15 pick in next year's draft. Even with all the "clutch" plays Stanley had in his career he ended up getting picked in the very late 7th round. Not saying where Stanley ended up is bad either, just saying scouts are obviously thinking Purdy is a better QB than Stanley, even though Stanley is a more prototypical NFL QB.
Either way, you have your opinion you're set on and isn't going to change from me trying to persuade you right now lol. Brock hopefully will have two more years to change your thoughts.