The only way I could contemplate a half-orc or half-giant/ogre at this point would be if one was petrified by an evil wizard to serve as a library statue for this many decades or frozen in an avalanche to be thawed out Captain America style. How many decades has it been this far? 40-50 years? But then you'd be property of Stygian. He's a harsh taskmaster.
Tieflings and Aasimar are at least partially planar, so might very well age like elves or dwarves or at least halflings, so they could still be alive and spry enough to take up adventuring. Though I'm betting they're on the chopping block since the fiends and celestials have been revamped for the setting... no more baatezu or tanari. Of course adventurers have iffy lifespans. Moraken's human, after all, and he was doing things long before many elder elves were born.
It would be interesting however to say no more half-orcs and get patted down by one in front of Vehl, or fight them in the thousands upon thousands of bandit spawns, so it might be less of a headache just to let half orcs breed with themselves and procreate that way. Otherwise, people wanting to play them will keep asking "If they were so rare, how come I kill 500 a day?"
The half elf npcs at least look either human or elf, so it's not as much an inconsistency, and they have decent enough lifespans to still be around. I think they and all the other half-breeds are sterile however, so their days may be numbered. I seem to remember a pink haired grub eating girl who couldn't breed a few years back.