There are a couple of places where the equation breaks down.
N = The number of solar systems where electromagnetism is detectable. This just counts planets we can/have detected, not the planets we can't or haven't detected.
R* = The number of planets suitable to support intelligent life. But this is life as we know it. Carbon based, and carbon is just one element. There could be a lot of intelligent life out there based on silicone, water, or iron... for all we know.
Take these numbers as Drake intended and there's still a possibility of life out there, numbering in the hundreds of thousands just in our galaxy.
That said, it's debatable there's intelligent life here.
