You might want to check out our service, Klaviyo, and specifically https://www.klaviyo.com/features/integrations. We do exactly what you're describing around connecting your data with data from the all services you use. I definitely think it's the future and the future is coming sooner rather than later.

I also agree that metrics are not nearly as powerful if you can't tie them directly to action. Which is why we built our own, fully featured email solution so you can go from metrics, to important people to engagement automatically.

That's where we think things are headed and it's going to be incredibly empowering.