I disagree. If things went the way we think they should have gone humanity shouldn't even exist. Billions of years ago some alien race should have mined out this entire solar system.
The fact that we are here and we have no solid evidence of aliens shows that something is very wrong with our understanding. Distances mean nothing when you have billions of years even without magical FTL travel.
Put some basic numbers to it. The oldest piece of metal (shapes by humans) we have found is about 7,000 years. I am going to make it worse and assume that there is metal we didn't find 10k years ago. With nuclear propulsion ship the nearest star is reachable. Let's assume it takes us with travel time 5,000 years to do this. Humanity goes from copper to two star systems in 15k years.
Now earth is going to be lazy and wait another 15k years before doing this feat again. Our new colony needs to grow so I am going to give them 15k years as well. We got a pace now. The star systems we have will double every 15k years.
Let's round down assuming some colonies fail and it makes the numbers easier. In 150k years humanity has 1k star systems. As a point of reference that is about the time difference between us and the first homo sapiens sapiens. In 300k years we have hit a million. At 450k years a billion. About 550k years, depending on how many stars there are in the galaxy, every star is now populated. 1/1000th of the time required from the Cambrian explosion until now.
From our understanding life was possible in our galaxy many billions of years ago. On average stars have 1.2 planets. There are about 100-400 billion stars in our galaxy. Of those about .2% are candidates for life. Based on our solar system there is about a 20% chance of life given the right conditions. From our dataset of 1 it takes 4 billion years to get sentient tool making social animals. Low end estimates of the number of aliens like us number in the thousands AT THIS MOMENT.
Again. We should not exist. Something is very wrong with our models. I am positive we will find the answer one day and I am betting it is going to break a whole bunch of theories.