I think there's something to be said for both subscriptions and a la carte. Subscriptions make sense for content producers because it gives them recurring revenue. It also makes sense for consumers because they don't subscribe to learn how to do one thing. They subscribe for the guarantee of a consistent flow of knowledge -> long term learning. I think of a la carte video as the equivalent of a Stack Overflow Q&A. How likely are you to buy a $6, 15-minute video on how to do x with y the first time you see it? The real value comes when you have such a breadth of these 15-minute videos that the content library begins to form a comprehensive reference for various bite-sized pieces of knowledge that users will ultimately need.
This is what my co-founders and I trying to do with Bitcast(https://www.bitcast.io). We're finding that model works well, and it definitely offers both consumers and content producers a different business model to interact with.