In all my experiences, I've
never seen a standing shot evaded. My Luck isn't overly exceptional, but I'm pretty sure that's working as intended. AC's currently intended more as an equalizer towards criticals. Sure, it only works moving, but it comes into effect a lot even if you aren't melee or close range. Perhaps eventually to some extent armors could be included for AC calculation resulting in occasional evades otherwise. I suppose it's possible currently, but the odds are highly against it occurring and I'm convinced you could invest dozens of hours or more and never see it happen standing still.
So I guess I'd like to say you're correct in your reasoning to say it's almost no chance and slightly effective at best.