Email marketing can be tough at times -- I'm right there with you. But by sending compelling offers to the right target segments and paying attention to the little details that go into an email, you can increase the opens clicks in your emails and generate more leads. (And learn more about which email marketing metrics to track -- and how -- here.)
You can assess the interests of individual list members by monitoring which pages they land on, and where they go from there. The process is explained by this example from Airbnb. They use click behaviour to ascertain the destination preferences and travel styles of customers and base their follow-up emails on those preference profiles. It's intensely specific, but it gets results!
That isn’t to say that sales-y promotions couldn’t ever create results—as marketing “gurus” have proved. The results just aren’t as good as they could be. Take the biggest gurus’ results—the ones they boast about—and calculate their conversion rates. Often their marketing is comparatively ineffective. They just have massive volume, so the sales numbers are impressive.