It is a bit unrealistic, but what is the solution? Should halflings be limited to a maximum strength of 16 or 18? Or be allowed to have STR 20, but have disadvantage on all STR checks (including str-based weapon attacks)?
These changes would make the races more 'realistic', but they come at a high cost for player options.
Older editions had a lot more pro/cons going on for smaller characters. Smaller characters got bonuses to dodge AC and other benefits, while also having penalties to other things like lifting, carrying, or even what weapons or armour you were allowed to wear. weapons used to have sizes, and unless you invested your feats into doing so, a Halfling or Gnome could never properly wield a large weapon.
But it was easier in the older editions to make dud characters that were just very bad, by not allocating your skill points right, or not taking the feats in the right order *cough*FuckingWeaponmaster*cough* or just by picking the wrong race/class combination it was very easy to make a dud character. I can understand WOtC trying to implement a system where this happens less, because it is very frustrating to build a character up and then realise that you did it wrong by mistake, or that Harper Agent is a shitty prestige class and you should have gone with the Bard/Duelist/Weaponmaster combo instead I'm not projecting at all.
I've never been a fan of hardcore immersion ultra hard survival realism simulator. I like fantasy. I've said before i don't hate the tasha's ASI rules, I can see why people would use them, but I probably won't. And if lots of people like them then its fine if they are added to the game, as long as I can have an opt out option.
