Physiotherapists get quite a bit of money buts it’s finding the customers that could be slightly difficult, like getting your name out there with good reviews. It’s also very rewarding as your helping the animal be more comfortable and relaxed
From my experience I have to agree with Caoimhe Sweeney, in my country (Ireland) many grooms are underpaid and overworked.
As for good job prospects- with horses it is very different to start a career in horses without large financial support. Private Riding instructors can earn a good bit but it takes a while to build a reputation
From my own experience, you're lucky to even get paid money when you're a groom and if you do, it's usually just enough to cover food for the week. Unless you're going thoroughbred sale prep, or the sales themselves, I've found sport horse jobs to be very poor pay unless you get lucky, particularly for the number of hours you put in. Maybe that's just my country though.
From what me and my family have experienced training horses is a good way and also a groom has good pay and is rewarding too!
Hope this helps