This thread has become a bit of a train wreck, and my apologies to the OP.
I love working with young and green horses and have done it quite a bit. But you know, my riding, my tact, my skill improved dramatically when I bought a schoolmaster, the horse that would reward me for doing it right.
When I’ve gotten on green horses since then, it is easy to get them round and comfortable and fluent in a way that younger me who knew only raw horses never could.
For most amateurs, and especially in dressage, we only have access to one horse at a time, and it’s usually a horse we own. We don’t have the time to ride multiple horses daily even if we had access to them. In the US we rarely have schoolmaster lesson horses or even the chance to hop on another rider’s horse.
I was never so humbled as the day when my trainer put me up on her FEI horse. It was a great perk for me but also it was her chance to see if she might be able to sell him as an amateur horse. I only had a handful of lessons on him but I learned so much about how challenging it was to ride this very hot and reactive horse especially if you just wanted to trot down the long side straight.
To become a capable, kind rider, you need those schoolmasters in your life somehow. I wish I could have do-overs on those young OTTBs I was entrusted with.
Anyway: Potential is expensive. Good teaching from both horse and human is harder to come by than it should be. The first six months with a horse is usually What Have I Done? as you build a partnership. Expensive horses create some bad emotions when things don’t go well (the horse does not know what he cost you). Horse shopping is hard.