I do not envy teachers the task of predicting grades. On the one hand, they wish to support students, but on the other hand they do a student no favours by pitching the prediction too high. It is perhaps difficult for a teacher to disregard the result of a mock exam, which is intended to simulate the difficulty and conditions of the real exam.
Perhaps in a society in a which resources were distributed more fairly, and in which higher education was a right and not a commodity to be bought, all those who wish to apply to university would do so with achieved grades, and everyone would have a gap year. Perhaps (say) six or nine months of the gap year would be publicly funded. People would do organised charitable work, or maybe attend some courses on non-academic adult skills.
Research suggests appears that our brains may not form completely until we are in our twenties, Perhaps we are all in too much of a rush to enter the world of jobs, mortgages, life insurance etc.
In the present system, the business of hunting for offers and waiting tensely for grades imposes a lot of anxiety on people.