A memorable example which comes to mind is the Curiosity Box of Vsauce... We are talking about that sort of thing right?
The Curiosity Box is a really nice product, but here's my experience: making products is ridiculously hard. I've made 23 different products in my entrepreneurial career, across almost every industry and category you can imagine. Physical product creation is especially brutal, and has a lower profit margin. Digital products have better margins but are also hard to produce.
The best products for 90% of content creators have already been made by someone else, but you need a lot of knowledge about affiliate joint-ventures and where to find those products (notice I'm talking multiple products).
The best way to convert these products is through email. With a smart marketing process you can literally ask each subscriber what they would pay for and then automatically recommend it to them and convert. I've seen this work over and over again. You can't do this in your videos because then you look like a sellout--some people get away with it, but only when their channel is already considered a product review channel.
Consider email a private room where you can grant wishes, and the internet is a magic genie that grants those wishes to your subscribers, while providing you with some of the revenue. Your YouTube videos establish enough credibility or interest to attract people into your email list.
When your audience gets big enough, or you have enough interest and credibility to justify the investment, you can make and sell your own products, PLUS you can open those products up for other people to sell as affiliates. This is the place everybody online wants to be.
