This is such a silly thing to argue about. Sales are very dependent on product quality, availability and dare I say delivering features customers need when they need them.
With sales, it is very easy to tell which specific people are responsible for any specific deal. That's why sales compensation usually includes a share of revenue.
With product development, unless you have a very small team working on the product, it's nearly impossible to tell which specific people were responsible for a specific chunk of revenue. When someone buys a product, it's hard to determine which specific features were responsible for the deal.
With sales, it is very easy to tell which specific people are responsible for any specific deal. That's why sales compensation usually includes a share of revenue.
With product development, unless you have a very small team working on the product, it's nearly impossible to tell which specific people were responsible for a specific chunk of revenue. When someone buys a product, it's hard to determine which specific features were responsible for the deal.