There are some amazing developers are also happen to be amazing marketers. Through their hard work they have built communities that derive tremendous value for users/buyers/customers.

Guess what? This is an effective marketing tactic. It may not look like it, but it is.

It is different from "closed source" marketing because the customer is assumed to be an equal and therefore a valuable contributor to the success of future product iterations.

One difference between "closed" and "open" source marketing is a perceived level of respect for the customer.

If we define marketing as hucksterism, then yes, you could claim that marketing is dead.

However, if convincing the customer to become an equal participant in the development cycle remains a challenge, then long live marketing.