Let me take it a step further and propose that even if we did develop interstellar travel, it would be far more practical and economical, and probably have a better expectation of survival, to simply infect a big mass of frozen rocks with our DNA and jettison it out into space. I mean, if all that matters is perpetuating our DNA elsewhere in the Universe.
Sure, but that wouldn't really count in most people's minds, for exactly the reasons I gave in the OP. It isn't them experiencing it first-hand or second-hand, so it's unlikely to ever be a thing we do.
It's probably far more likely than actual interstellar travel, though. But if we get to that point... what, really, would even be the point? Why undertake something that is such a massive resource-drain using actual meat animals who will never experience the joys and rewards of finding new planets?
But here's another thought, which oddly you pooh-poohed the first time I mentioned it. Any solar systems with life-bearing planets that are near us enough to reach us within a time-span that might make it possible and/or worth their while from an ego-perspective are about the same age and stability as our own. That means that the geological processes of their planets have also recently chilled the fuck out enough (literally) to give the latest round of life forms a chance to maybe evolve high levels of intelligence complete with a sense of self. Now, lets look at a fairly simple rule in biology; if it can be shown that something is
, the most likely condition is that that condition is what is most likely. In other words, the unlikely is unlikely. That means that by virtue of existing, life is likely, and that life as we know it, having been observed, is already more likely than life that is unlike anything we've ever seen. While we don't know
, we can at least reasonably guess that we may, in fact, be fairly representative.
That's not a very sexy notion, though, so until/unless we actually meet spacefaring species, we will probably continue imagining them as unimaginably strange.
Just an aside, but the age of the universe in general does not promise a much-earlier earlier existence of solar systems with planets capable of sustaining life. The early Universe was probably a much more hostile place.