Here's the whole point of bolt vs semi auto: Can you reliably work the action on the bolt, and can you do it for a potential follow up shot as quickly while still staying on target?
Lots of deer don't stop moving, first shots are sometimes deflected, there are any number of reasons why an accurate second shot may be needed. If you are always certain of getting the first shot, then of course, a muzzleloader could be just as much a possibility.
Lots of hunters buy into the sporting tradition in firearms, but they sometimes find themselves shorted when that one buck comes into play, and one more shot would have anchored him. On the other hand, too many buy semi autos to spray and pray. If anything, those two groups need to switch over. It would improve them both.
Self disciplined, careful hunters would be better served with the more reliable semi auto action. They will still choose their first shot carefully, and they will more likely not short stroke the action or get it jammed. Semi autos are usually closed top receivers with only an ejection port. Bolt guns are exposed and vulnerable to the environment.
And, back to that second shot: Do you want to move your head to avoid the bolt while that deer is stepping smartly into the underbrush? Or would you prefer to keep the crosshairs on it?
Again, if first shot hunters are that good, why do they load another round besides one in the chamber? Their bolt gun doesn't need a magazine feed. They are that good.
Or, knowing anything could happen, they prepare for it, and hunt with a gun that minimizes loss of game.
Not the usual view of it, but there is too much complacency and not much thought about what we are really up to.