Lanefan
Victoria Rules
A moderately strong Human is IMO in the 14-15 range. That getting way up there for our little Halflings who in 1e would cap right out at 16.No edition of D&D has ever modelled this. Ever. Literally 100% of editions have not represented this, or anything remotely like it.
Because 12 Strength isn't, and has never been, a meaningful ceiling for halfling strength. Even in 1e, when ability score limits actually existed.
Indeed; and in saying it this way you've almost made my point for me.Why should they? PCs do not behave like those populations. They do things that most members of those populations would consider completely insane. They take incredible risks, reach stupidly high heights, etc. They should not be like normal people--because normal people don't adventure. “We...have no use for adventures. Nasty disturbing uncomfortable things! Make you late for dinner!”

Adventurers are different because of what they DO, not because of what they ARE.
What they ARE, ideally, is a random (and thus, reflective) sampling of their species' population other than they each happen to be particularly adept at...something, whatever it may be. They each have a special talent for something, and otherwise are mostly ordinary people.
What then sets them apart in their world is what they DO: they take that talent and put it to use in the very risky field of adventuring.
A Halfling, yes. An exceptional, unusual, one-in-a-generation Halfling.Okay. D&D has never done that though, and it seems odd to demand that it start doing so, at least in the way you've described. It is trivially easy for a halfling to be stronger than an ordinary goliath, and always has been. Even back in Ye Olden Dayse this was true. Only noticeably above-average goliaths (or equivalents, since I know goliaths don't exist in 1e) could ever be beyond a halfling's reach.
But if the Halfling strength range is 3-16 and the Goliath strength range is 8-22 (which is probably about where I'd put them were they in my game) then the very strongest of Halflings (at 16) would be only just above the average for Goliaths (at 15). More importantly, the average Halfling would be significantly less strong than the average Goliath.
With a simple +2 bonus, 5e never separated them to that degree at any point; but at least they waved at the concept as it went by. Not any more.