Well apparently their strategy to ensure survival didn't do too well since we're discussing an extinct civilization here.
Maybe they're "extinct here", because they just left.
BTW. this is actually a big theme in David Brin's Uplift saga[0]. Basically, you have all these alien civilizations, more and less friendly to each other, but bound by some common rules, some of which regulate sustainable colonization. This includes an exclusive right to settle and use a habitable planet with a biosphere for $whatever number of millenia, and after that time, the civilization there is supposed to pack up and leave, fix environmental damage, and erase any trace of their existence, commonly achieved by dumping everything into the planet's subduction zones so it gets naturally recycled; after that, the planet is to lie fallow for ${some other number} of millenia, to give nature a chance at creating more biodiversity and stuff.
Quite ingenious setting, if you ask me.
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I'm guessing you've not read them?
The gimmick of the series is that all sentient species were uplifted from non-sentient animals, and they were uplifted by species that were uplifted, which in turn were uplifted... and none of them knows by whom or by what. The "progenitors", the hypothesized first sentients that uplifted a presumed first generation, are lost to prehistory and nobody knows.
So there is a shared culture and a small degree of shared biology, because each generation of uplifters uses existing models of sentient species to model new sentient species. There are only so many ways to invent the wheel, although Brin was very imaginative indeed in this.
Humans were not uplifted; we're called "wolflings" and as a terrifying novel abomination would have been exterminated upon discovery, were it not for the novels' future setting having us already started work uplifting dolphins, chimpanzees, orang utans and a handful of other species. If humans were not a progenitor species the aliens would have extirpated us -- but we have client species of our own.
He does have answers to most of the objections one might come up with.
Brin's ideas were influenced by Larry Niven, and riffed upon by Terry Pratchett in his early SF works. Later Brin novels riff on ideas from his own earlier ones.
In their time, in the 1980s, I really enjoyed them. I own them all, several in hardback. I haven't re-read them in decades so I don't know how they hold up, but Brin is alive and still active.
Anyway, point is that for the kinds of races likely to get their manipulators on a fresh planet, direct colonization is often way down their list of priorities. (And perhaps most of their population is already in a Dyson swarm or something.)
Also, the deep history of visits means there's been time for a lot of similar biology to spread around.
There are also significant numbers of extremely agressive and militaristic civilisations, mostly held back by the laws and customs of setting, who would gleefully seek out and destroy anyone not following along.
Not necessarily. They could have existed hundreds of millions of years ago, and become victims of the Chixhulub asteroid impact or other huge natural disaster after successfully maintaining an advanced civilization for hundreds of thousands of years, FAR longer than our probably ill-fated civilization has managed. They might have also left the planet. Or they could have transcended into energy beings.
There are >1 ways for a civilization to become extinct.
Another intriguing possibility is some sort of senility setting in after long-term evolutionary success. The intelligent cephalopods eventually got tired seeking answers from a mysterious Universe and settled for the quite life.
We aren't doing that well either. Too early to tell. But I think we've shown enough problems to at least speculate on how we will do during the coming 'great filters'.
"This is what de-growthers actually believe."
The beliefs described by the parent are basically the de facto beliefs of everyone who believes the climate crisis can be solved through some form of accelerationism.
I don't think there's even a question that the only proven method of reducing emissions and slowing climate change is to leave fossil fuels in the ground (which is by definition de-growth in practice). But there has never been any remotely serious will for actions of this nature.
All evidence thus far is that it's not happening, no one even votes for that under democracies.
So far, all evidence is that we can pass laws, create engineering, and cause behavior change that leads to reducing carbon emissions without hurting growth.
If you care about reducing carbon, the strategy of "destroy capitalism first" isn't going to happen at all, and especially not soon enough to have the impact you want.
Green growth people (like myself) argue that we can grow without incurring the negative carbon impacts given proper policy / tech.
We very much want solar, etc. technologies that do this. Degrowth isn't the solution.