It seems like chocobos are the "loser"/"poor people" mount now, and then there's premium mounts like unicorns and couerels for paying more $.
Kinda wish they had just kept it to chocobos with different armor and colors but whatever.
It does seem like there are going to be quite a variety of mounts running around from pretty early on, but I suspect that we'll still see a fairly large number of people using chocobos. I think the barding options will probably make them feel a bit more customizable, and I wouldn't be surprised if chocobos were the only mounts you could name yourself.
And I can't say for sure, but I haven't seen anything about using other mounts as NPC companions/buddies. Chocobos might still have a monopoly on that market.