Not at all. Sometimes the wiser choice with the most chance of success and least chance of failure is valor. If the horse interprets the wise choice as timid, it can be as bad a choice as valor depending on circumstances. Making the wrong choice doesn’t make anybody a fool either. As long as the rider realizes they chose poorly, contemplates why they should have chosen the other and learns from it, it’s all good. That is how you really learn, by doing, not reading.
This isn’t as much about the choice to get off as much as choosing to ride that horse in that field on that day. The best time to make that choice is before you get on. Sounds like you are understanding this is a valuable lesson as you progress in your riding journey. You did reach out in here for ideas, that’s a sign of a thoughtful rider who wants to learn.
Oh, the set them up for success every ride, never let them fail? Though very familiar with the concept, I never heard it expressed that way until I had about 40 years in the saddle. From Melanie Smith Taylor, one if the first seriously successful women in International Show Jumping, whose poster aboard the fabulous Calypso graced my tackroom wall decades ago. She was working with a developing riders clinic, maybe 6-7 years ago, over several days…a week after she finished the NYC Marathon. One must always consider the source of any advice…thats a pretty solid one.