Product Shouldn't Be Left to Product Managers

This times a hundred.

Product thinking means thoroughly understanding the domain you’re working at, knowing the market your domain is part of, and how your product contributes to the overall business model and strategy. You need to actively keep the customer needs in mind and leverage input from product stakeholders and engineering leaders to determine the right technical solutions to deliver customer value quickly.

The main point of this article is that as a developer you need to really understand the product. You cannot defer that to product managers. They are part of the team too, but in a great team everyone cares deeply about the product the customer is going to use.