They may simply not agree with the conclusion, or the end. It's pretty hard to have this discussion without crashing into the nature-nurture debate, but one could be interested in a particular result, not merely _any_ result, and they may perceive a lack of something blocking their way towards that.
Not to mention, we do not really live in a world / society that recognizes this, and social approval + hireability dramatically affects one's psyche, more so than mere rational thinking.
This doesn't count efficiency and optimization. It was just that given enough time and resources we are capable to "do something".
It's hard to learn that hard work will beat aptitude for a skill and that we actually have limited time in our lives though. But as you mention it makes a difference in the mind of people. The mental blocks many people have against learning new things really hinders how people interact with this rapid changing modern world and with their social groups. Also, there's these kind of realizations that humbles you (or lift your spirit up) and helps you being less egocentric, more empathic and forgiving.
I think bringing down these walls is a really hard problem.
After meditating / contemplating this for quite some time, we are talking the order of months. I realized that even if someone knows 1000x more, they still may not know your niche. More than that, everyone has niche expertise from their lives, which no one else can access (from their experiences).
I don't know how I got to that conclusion, or how to explain it. It was the hardest problem I solved, because it's something that had to do with a change in perspective and personality. It also is what helps me listen to others in debates and to be much more open minded. I wouldn't say it's that big of a deal, as I felt it was part of growing as a person, however many around me don't seem to recognize that. When I hear "they are naturally gifted" or "I'm not smart enough", I feel those are people who haven't had the same realization (i.e. experience).
Anyway, that was probably the most difficult and profound problem I solved for myself. What motivates me.