I think the main problem why this is not active for everyone is maybe abuse.
If anyone can add scripts to their landing page, just imagine what will happen to all the landing pages and the liability Envato would expose themselves to.
Also, not sure if it’s that relevant (statistically speaking) for low level authors.
Not saying it wouldn’t be nice though…
Maybe an integration where you just put your tracking ID like Udemy has would solve many of the problems and allow more authors access to advanced tracking.