Because planets suitable for life could have formed several billion years before the Earth. Our solar system is relatively recent. I don't know when rocky plane

Because planets suitable for life could have formed several billion years before the Earth. Our solar system is relatively recent. I don't know when rocky planets first started to form, but I've heard for at least the past 10 billion years. Also, we don't know what evolution always takes as long to result in a technological species. It could be tens of millions of years slower or faster, just depending.