I have never had a horse groomed and tacked up for me in 40+ years of riding. I started at a farm that taught grooming and tacking and expected you to do it as soon as possible. I’m sure I had lots of help when I started at 6 years old, but I know for sure I was easily doing it all myself by 10 because I rode a horse that would lift his head too high for me, so I had to go through an elaborate ritual of tying him short, climbing up on the door, putting the bridle on over the halter, then undoing the cheek pieces one at a time to get the halter off from under the bridle.
I did work at a high end dressage barn where most horses were investments in full training with only the trainer. There were a few owners who came to ride, and we were expected to have their horse groomed, tacked and waiting for their lesson. We also tacked up for the trainer, since she rode one right after another. However, there were two local older ladies who didn’t want that, and would spend quite a lot of time grooming and tacking up before riding, because I think they just liked to spend the time with their horses.