It also depends on how difficult the monsters are. AC is difficult to raise, while attacking accuracy increases fairly easily. At high levels, I find that AC becomes less useful in favor of other measures. I mean, hells. Its one of the major arguments centered around Great Weapon Mastery - at high levels, the -5 to hit is negligable compared to AC.How much that matter starts to depend on the campaign, and the party, not the character. A party that's light on healing resources can't afford to keep a party member like that up. A campaign that tends towards the 5MWD has no problem with it (thanks to full overnight healing).
As such, AC becomes less less important at higher accuracy levels for many. Games do vary wildly enough that there's no standard answer, but even with as much standardization we can make between games, the answer is still going to change greatly depending on factors like level or preponderance of Saves versus Attack Rolls. OR, heck, even against enemies angling for Advantage on their rolls like PCs do.
As such, white room benchmarks aren't a factor I really feel do justice for the argument.