You should broaden your mind. There are plenty of horsey jobs without needing to be the best rider. You could be a groom, stablehand, equine nurse/vet, equine masseuse... But none of them are particularly well paying jobs. One of my TAFE teachers multitasked and made a good living for herself - she was a teacher, a competitive show jumper, and ran an equine massage business. Another was a teacher, trackwork rider and racetrack clerk.
I have problems that restrict me from physically working with horses, so I'm opting for the next best thing - administration on one of the large horse studs.
Honestly, horses are better as a hobby unless you have a lot of money to back you and a heckload of talent. But even so, there are plenty of options. Volunteer at a horse rescue. Find a horse breaker that could use an apprentice. Work on your grooming skills and become a professional groom. There's always a way to keep horses in your life.