I think ads on Gmail are also a thing of the past, aren’t they? The answer to your question is: no income. But you’re having a constant time share lunch with Google to actually buy a share in a beachfront condo. By which I mean subscribe to their cloud and AI plan. Or YouTube. Or their business suite. Etc. And then they have converted you to a paying customer. The free service is an investment to get you hooked and then paying.

And in the meantime they can collect some data from you so when you’re faced with ads they might be more effective.