Arguably, they already do. They pay us in services such as communications software, social software, search, etc.

Also, this is very common in some countries/industries. In the U.K. if you want to buy insurance or open a bank account etc, you’ll often use a comparison website, and they will likely give you an incentive (such as free cinema tickets) for choosing a service through them. This is paid for directly by the affiliate revenue. Cashback sites also exist that do this through affiliates. Credit cards do this with air miles, cashback and other rewards too.