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In addition to the probability of an earth-like planet (which you propose is very low), there is also the issue of life springing forth (from dead stuff), even when conditions support life.

The chemistry of a self-replicating "thing" is pretty complex, involving the "thing" that replicates, as well as a protective shell. The simplest "thing," a virus, can't replicate without harnessing some other living thing's energy factory.

Even though the universe is immense, it's possible to estimate the number of atoms, starts, planets, etc. ... ends up being a big number, I think the number of atoms is estimated to be 10 to the 50th power or something like that. Then, do the probability of the chemistry of self-replicating (not intelligent, or even self-aware) thing. That's a very small number, but, in light of us being here, not zero.

I see God's hand.

I think there is probably plenty of life around but next to none with the tech to do radio.

I think dogs are pretty intelligent but they are no where close to doing radio.

the dinosaurs had 300 million years to develope radio and from the fossils, they never even developed simple tools or built buildings.

the shell or cell membrane is a phospholipid bilayer that can occur in nature without life.

The lipid bilayer is a hydrocarbon that floats on water and can form spherical shells when water droplets (rain or splashing water from the ocean) fall on it.

Even though the universe is immense, it's possible to estimate the number of atoms, starts, planets, etc. ... ends up being a big number, I think the number of atoms is estimated to be 10 to the 50th power or something like that. Then, do the probability of the chemistry of self-replicating (not intelligent, or even self-aware) thing. That's a very small number, but, in light of us being here, not zero.

You aren't even close. A quick Google search shows 10 to the 49th power as the approximate number of atoms that make up Earth. Just Earth. And current estimates have 100s of sextillions of stars. Assuming a 1:1 ratio for planets, that's quite a lot of chances to have some form of life.

But how can we 'discover' these other life forms? Or more likely, have them discover us? Considering the nearest star is just over 4 light-years away (which means it takes about 4 years for it's light to get here), and most stars are much farther away. So any EM connection would be from some life from long ago. Our signals to them would have the same delay. And unless you have a very tight transmission, the power of the signal degrades considerably at any distance, so most likely any signal would be lost in background noise. And physical contact would require thousands of years of travel, unless some kind of light-speed or greater than travel is/was developed. Like looking for a needle in a haystack the size of Jupiter. A tiny needle.

The only way I think we'll ever discover any kind of advanced life is years and years down the road, once we've started actually colonizing other planets and we'll eventually run into something else. But for now, our best bet is microorganisms on asteroids or Mars.