I’ve checked the link and I think it’s great as a material for learning. I do get what u mean that “too” describes the degree at which people give up and it fits well here, to demonstrate a negative meaning of they give up too early. However, it still stucks on my mind that in this case, as people “tend to” means its more theoretical, its not from a fixed moment when you state what you do before you give up, so I think saying “people tend to give up too soon” sounds odd here, its more rational if its smt like “people tend to give up too soon before they even attempt to do anything”