No one is more outspoken on this subject than I. Still at 3307, its not barely 3 yrs old yet. 6 years being the swing date for many and 10 years being the drop dead date.
If you don't plan on wearing it out before 10 years are up, you may have a case for a fresher tire. If you wear it out before 6 years, no harm no foul.
I agere with your sentiment though and everyone should be educated enough on the subject to check the date before buying the tire.
That is a little too old to be on the shelf. But once the dealer buys it they can't return it, so stocking tires is problematic especially for a small dealer.