When I first started out in making content, things were a pretty simple. I made stuff, I created a product page and I got paid. Well that's an oversimplification, but that's essentially it. For a while, I was happy with that. But there were some things that made me re-align my thinking to going independent.
The first and most important thing, was getting paid. I am amazed at how many content creator websites have what I consider to be unreasonable processes for paying their content creators. I don't like being cut off from the money I am earning by someone who holds the Sword of Damocles over my ability to ear. I call it being at the mercy of content selling websites. A lot of times, I found myself not being paid on time, or earning far less that I should be earning because of payout percentages. You're doing 90% of the work, but you're not collecting 90% of the royalties. Most of the times, sites only advertising on your behalf is a mailing list, or relying on people who know the site is there. That's not real justification for taking more than half of the royalties for the products I spend so much time creating.
The other part of it, is that for a digital product, I'm forced to sell it for what these content sites consider the value to be. I'm not greedy. This is a second income for me and I know that products are more and more expensive every day. But here's the thing --no matter what the "industry" puts out there, the only thing I'm really expending is my time and expertise --which costs me nothing but time. I tend to want to price what I sell reasonably --which often doesn't jibe with what content selling websites want. This way, you're paying me and only me for the work that I do. That means I can afford to charge less. I'm not a big corporation, so I don't need you to fund a whole corporation.
I still sell on content sites, and if you want to buy there then that's fine. But I want to reward my fans for supporting me by charging an affordable price. If you want to buy on Gumroad, Cubebrush or Renderhub --that's fine. But if you buy from me, then you're going to get the same value for the absolute lowest cost. It's my way of making a dent in the expense of being a 3D hobbyist.