I have been training horses since 2016.  I've recently started a push to get Krogdalo's Sanctuary completed and reach Guru Training.
In 5 weeks, I've gone from Master 4 to Master 10, while using stonetail meals, fiery celerity draught, and mount exp scrolls.  I have full IV manos gear and preonne accessories.  The terrible exp rate aside (compared to Fishing as an example > wife was guru within 2 weeks), I am constantly bottle-necked by Royal Fern Root. 

Horse Races don't happen unless carefully co-ordinated through guilds (I've sat in queue and re-queued for hours),
dailies and weeklies only net 92 Royal Fern Root per week,

and i have over 1500 Flower of Oblivion rotting.

It is bad enough that nearly every T10 seems to pity out at 30+1 attempts, the least you could do is make attempts not time-blocked.  I don't care if there is effort or quests involved, that is fair.  But time locking this content really makes me not want to play.

Once they gave out a T10 for free, it was time to remove the time lock. Hopefully one day.

I'd quite like to sell them since I have zero interest in horsing about

What are you doing with your Ferns? You say you've been training horses for nine years, so you should have way more than you'd ever need.

Even at Guru, you only get 99 ferns for the week. Talk about spitting in your eye. That's without the aforementioned race weeklies... that people aren't doing and you might get lucky doing 1 race.

Let us sell the ferns. I'm sitting on almost 20k and I'm not making another T10.