Akaso isn't a "simple" material; it's used for high-end clothcraft skilling to make akaso thread/cloth, which also happen to be needed for geomancy AF gear. When SoA was first released, akaso was in high demand for these reasons, and farmers and crafters both made fortunes from this. The demand might be less now, so you're having a harder time finding it on the AH. Yes, it's annoying to go to Yorcia Weald and harvest them, but plenty of farmers and crafters have done it. I haven't bothered in a long time because I can get it much more easily (albeit infrequently) from my mog garden.

You might be lucky and have SE make akaso available some other way in the future, but I wouldn't hold my breath. They just made 3 ingredients available from cooking guild npcs with this last update, but those items have been around since CoP/WotG and are only now getting attention.

Also, you may already know this, but revival roots are easily farmed from undead (go to any zone with ghosts, dogs, or fomor and you'll accumulate a ton). They may not make this available from vendors, because it's also used as a proof of bravery to unlock PLD job. I've never understood why onions weren't sold by npcs (maybe because of the FF franchise's strange fondness for onion items), but they made me some easy gil back in the early days of the game, when I would farm goblin thugs in outer horu towers.