Humans are extremely bad at thinking about long periods of time. The modern industrialized world is maybe two and a half centuries in the making. Meanwhile the Earth is 4.5 billion years old. If we manage to maintain our current population for the next 4-5 billion years until the sun expands, and destroys the Earth, there will be another 160-200 _quadrillion_ humans.
Do you know how many a quadrillion is? Neither do I. If we do the ol' seconds conversion, a billion seconds is 31.7 years. A trillion seconds is 31.7 thousand years. A quadrillion seconds is 31.7 million years. Which is enough time for another quadrillion humans!
Now there are 100 billion stars in the Milky Way. Some older, some younger, and there have ben generations of hundreds of billions of stars that have come and gone. Let's say they all have an Earth with Fours of similar lifespans an similar needs. What're the systems that let that cohort coexist and thrive?
And now let ask you. Does our collective experience of one planet, and one moon, and what we can see on a couple of other planets, near one star seem sufficient for understanding the entirety of whatever may be out there?
That's what thinking galactically means. Maybe. Just maybe, if there _are_ things to figure out, we haven't gotten to the point where we're going to be able to do so just yet.