We are not at all post-Copernican, strictly speaking. We value living things like we never did before. You occasionally hear discussion about granting rights to non-human animals: dolphins, apes, etc. That almost never happened in human history (save for a few cultures where certain animals are held to be holy). You are talking about moving away from anthropocentrism, while the scenario I'm describing is a bleak world where all life as such isn't valued. In that world, there isn't even any point of talking about "saving the planet," because "for whom are you saving it for? For polar bears? How are they any better than lifeless rocks: both products of geology?"
For me the respect, and awe, for life comes from how each individual is the proverbial snowflake, as an instance of life, and an incredibly complex, emergent and dynamic one at that.
Take something completely lifeless like a stalactite as a reference. Tehy can take millenniums to form, but the process really isn't very special, just water dripping from the ceiling. Which most people realize, yet most people still feel a certain amount of awe when presented with one, and would be appalled if someone just decided to take it down for no reason. That would be disrespectful.
It's the same thing when we talk about species going extinct. Most of us has no particular connection to most species, and shouldn't be bothered. But still, every species has its own unique character and beauty, which will leave an emptiness behind of possibilities lost, so is a sad thing to loose for that reason alone.
So I think discovering more instance of living things would not make life less valued, on the contrary, more uniqeness would only bring more things to be in awe of.
We will still think of species' as unique (identical biochemistry is exceedingly unlikely), yet life will become somewhat "commodified" in a sense, if you understand that comparison. Obviously, I took some liberty in describing a nightmarish "moral crisis" scenario; I am just surprised that my comment garnered so many responses, all of them misunderstanding my main argument in one way or another.
Only for abrahamic religions. Hinduism/Buddhism and other oriental/ddharmic religions repeatedly downplay our centrality.
Finding microbial life through the solar system won't really make us any less special. Even if we find evidence suggesting microbial life is common throughout the universe, it does not imply that complex animal life is common or inevitable. I suspect the goalposts will just be shifted. :)