No Stupid Questions

There were (and are) natural radio waves from things like stars and even something known as the Cosmic Microwave Background, the product of the Big Bang that created the universe.

However, they are not like rivers that we exploit for transportation, irrigation, and energy production. Instead, we have to generate our own radio waves to serve our specific needs.

In this sense, I find it useful to think of something like a lake. There are natural waves created by the wind, but I find it difficult how to imagine we would exploit those waves for communications because there is too much randomness built in and we have no control over the wind itself. On the other hand, it's relatively easy to imagine how we might create our own waves in patterns that can carry information.

An interesting thing about generating water waves to communicate is that it would be extremely difficult to make it work in practice. The waves degrade quite quickly over distance, so would need periodic repetition and amplification. Natural waves would mess up and possibly overwhelm our nice patterns. Other people trying to use the same body of water at the same time would be creating waves that would mess up and maybe even overwhelm our nice patterns. To get radio communications to work, people have to figure out how to deal with analogous problems with signal degradation and interference.