The solar system formed, apparently, 4.6 billion years ago. The universe itself is closer to 14 billion years old. Might a solar system like ours have formed, somewhere, 4.7 billion years ago instead? And once it's formed, how long does it take for life to evolve? If the earth had 10% more surface area, would evolution have occurred 10% faster? There were various huge extinction events during the life of the earth, at least one of which appears to be due to a collision with a giant asteroid; if that happened 70 million years ago instead of 65 million, would humans have evolved a few million years earlier?

The point is that, if you rolled the dice on a new universe that had a decent chance of producing something like our Earth, there are lots of sources of variance, such that the "95% confidence interval" during which something like us might have evolved is probably hundreds of millions of years wide. Given that, the chance that two independent civilizations would reach a particular level of technological development during the same million-year period is less than 1%.

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.

Because the universe is pretty old and planets similar to Earth but much older are probably abundant.

Consider how long the dinosaurs were around vs the short period humans existed. If another planet managed to skip over that long delay...