It seems like the attempt to gather compelling evidence ends up skipping over foundational elements. After all, if someone quits consistently then progress is

It seems like the attempt to gather compelling evidence ends up skipping over foundational elements. After all, if someone quits consistently then progress is likely to be difficult. The idea of grit potentially also connects with two other potentially interesting related ideas: First there is Victor Frankl's observation that those who were expected to survive in the concentration camps were the people who were young adults, healthy, well fed, smart, and quick. However, these people often reacted very badly to sudden change, chaos, and the lack of obvious opportunities and would end up dead in a week or two as much from hopelessness as privation. Meanwhile people who were skinny, weak, sick, and wounded often survived one trauma after another because they had something they were determined to live for--often family, sometimes cherished places or work. Something they longed to return to could keep them going. Second there is the actually rather robustly documented phenomenon of John Henryism in which people suffering from discrimination or lack of opportunity find success by expending tremendous effort only to fall victim to illness early in life as the tolls from their exertions accumulate. This is a good example of how the grit to success story could have a serious downside that should be considered even if the success side might actually be realistically and meaningfully obtainable.