Ideas vs Actual Stuff
Most people have an innate ability to assign value to actual things - a box of apples, a t-shirt, a car, a house, etc. It’s pretty easy to do, because , often without realising it, what we do is make a subconscious comparison to something similar and thereby arrive at a ‘ballpark value’. This is how houses are appraised, for example.
Ideas though … well that is something very, very different. It is difficult to compare ideas, particularly abstract ideas. People have a hard time placing value on ideas; after all, they weigh nothing, cannot be seen, and anyone - right - anyone can have them.