Limiting (let alone this severely) a number of functions a developer can introduce and locking them in having to pay recurrently just to overcome this limitation and keep their code working is insane. I believe this dooms the product to be extremely unpopular. This way people probably won't even invest time in giving it a try.

Real-Time Data Sources sound like a thing which can be a premium feature. Unlimited UDFs and Unlimited Commands don't.