I don't consider my characters to have all of the mounts that they have available to summon as a game mechanic, and not all of my characters have a chocobo IC. They will instead borrow a porter if they feel there is a need. As someone else pointed out, I also see it as something you could compare with having a horse - and some of my characters wouldn't have the time to properly care for a chocobo or a stable, nor the gil to hire someone to do that for them. If they do have a chocobo, then it's a case of it being stabled or tied up when not needed. Additionally it just doesn't come up a lot in RP for me, I am always fine with having my characters do a bit of walk and talk.
