So I have been reading of skimming books on herbalism and I am like how do I know they do not just make stuff up

All the tools to learn most of the book knowledge you can get from college can be found by buying information from other sources

But presuming the college information is correct you can save time by vetting out stuff people just make up with no proof

Perhaps the amount of time you save is worth the cost of the college degree if you can earn a certain amount of money with that time