Mainly due to mental worth/reward imbalances and a bazillion examples of "Lack of awareness" in action.

When the human psyche is paid and cannot draw a direct line to the work which produced the pay, there's a mental breakdown which occurs. Pre-payment, even for services which WILL generate worth, causes a lot of problems for most people's psyche. ;)

Most people grossly overestimate what they need and how much they should pay for it, when they have a significant amount of money to work with. The number of tools/resources which are purchased and never used is staggering. The number of people who find out they're not capable of finishing what they started is even more staggering. Craigslist, depending on your area of the country, will be full of grow equipment for sale by people who've spent thousands (and some millions) learning they don't know how to grow cannabis.

Crazy world we live in. I bought $17 worth of electroneum, to sell on the initial rise. ;)