Faolyn
(she/her)
Thanks for this @Faolyn. This is honestly, truly appreciated.

My belief is it doesn't matter if that number is dropping (according to D&D Beyond, which is just one platform that probably the majority of people don't use). There's still a significant number of people who play halflings.See, that's I think the crux of my disagreement. I don't think it's enough. And, I think it's a number that is dropping as years go on. Or, at least the percentage is dropping. But, I have pretty much zero proof of that, other than reading chicken entrails, so, I can't really argue with you.
That's true. But not for the Realms or Greyhawk, and probably most homebrew settings don't make as radical a change as Dark Sun does. In Eberron, the dino-riding halflings are definitely quite different, but I think the two dragonmarked houses--one for healing and one for hospitality--are halfling-y enough to count as mostly standard. As for kender. Well.That's actually not really accurate though. Halflings in every other setting are massively rewritten from the PHB. Darksun, Dragonlance, Eberron.
But anyway, that's kind of the point. Their traits allow them to be molded however the DM wants and as long as they retain their most basic trait of being the Small-sized, generally not-too-magical, human-looking people, they are still halflings. I think it's a bit harder to do that with other races like elves or dwarfs.
According to Wikipedia, it's in large part because in the early games, the ones that Hickman and Weiss used to prepare for DL, the PC halfling got a ring of invisibility and they felt it was too much like Tolkien. So they got rid of halflings and introduced kender. If only they had put a different magic item in the pile of loot!If halflings are included in the setting, then they are rarely PHB halflings, to the point of being pretty much unrecognizable as halflings. Kender aren't even called halflings.
So think about gith. They have an enormous ton of baggage with them that it's hard to get rid of. A while ago I was doing some worldbuilding with a friend of mine and I mentioned including gith and he immediately said something along the lines of that not being a good idea because then there would have to be all these mind flayers. I hadn't even thought to include that part of their history (I'm more for grabbing things that are cool and ignoring or changing as much lore as I feel like), but that was my friend's first thought.Again, you're comparing minor races like dragonborn, which have very short histories in the game, with one of the core 4 races. I mean, of the examples you gave, only the dragonborn and planetouched (tiefling) even appear in the PHB. We need to be careful to compare apples to apples.
Likewise, other monster races have so much history that you have to start out saying what they're not (always evil, controlled by evil gods, etc.) if you want them to be anything other than their MM-counterparts.
Fair enough. However, I think that in future editions they might very well keep on including new races in the PH, now that they have precedent. As for page size, D&D books will become more and more digital as time goes by, for better or worse, and the weight of the print books won't be as big a deal--leave that at home and take your book-laden device with you.Traditionally though, no you can't. 5e is the first PHB to add races. 4e added and subtracted. 3e and earlier never added anything that wasn't in 1e PHB. Five editions of the game and we've only seen one PHB that added races to the PHB. So, the idea that we can just add more races, while true, certainly isn't borne out by experience. And, three pages in the PHB is a LOT. That is a significant amount of space. It's not like the old days when a race description took up a couple of paragraphs.