Many of the people I've seen doing really well at university already learned about the subjects they study. A few studied in another country but couldn't get t

Many of the people I've seen doing really well at university already learned about the subjects they study. A few studied in another country but couldn't get the courses transferred. Another did a year of math studies before university at a local university, then went on to study engineering at an "Ivy league". And so on. Just spending 10 hours a week studying a subject for a year before someone start studying it at university should be a giant market. No need for diplomas.