Maxperson
Morkus from Orkus
For the general races, sure. But players aren't playing all halflings or half-orcs. They're playing PCs, exceptional individuals within the game. It doesn't matter than halflings are generally weaker than half-orcs in the broader population. The game is about this halfling PC being played by this player at the table and the PCs should not be so limited. That's why there are no stat minima or maxima for any PCs.
The PHB race write ups ARE the PC characters. It's the PLAYERS handbook

There is also no fluff reason for PC halflings, or any other race for that matter, to be different from the general population.