Re: Time to get started!
"You [don't] need oil to go to space. You can do it using light and water."
A technological society can't produce enough concentrated energy, power, to get offworld without fossilised sunlight, coal and oil, as start-up fuels. There is no way to jump from agrarian villages powered by animal muscles and wood-burning to nuclear power and lasers.
Once the rock oil is burnt, including that from shale, and the coal all used up there is no recovery.
Yes, *we* could jump into orbit using lasers and water-tanks but *we* have vast reserves of oil to power the lasers. It can't be done if your only energy supply is a horse nor if you are an evolved horse-derived beast and your energy supply is ape-muscles.
"What about solar power?"
Okay, but from what do you build the mirrors to concentrate the Sun's light? Again, it's easy for 21st Century humans because we've used 300 years of oil and coal burning to build up a colossal store of tools and techniques; it would not be so easy for Cephalopods just starting their societies some millions of years after us.
They would find it even more difficult than we did to start up as we have not only mined and used the coals and oils we have also mined the silver (to pick but one resource) they would need.
Building a civilisation like ours, a vast city-culture that spans a planet is relatively easy when energy is basically free and other resources are scattered within reach of a pick and shovel. When the only silver remaining that isn't in a toxic, radioactive dump is miles under the surface and minable only with 21st Century tech using it as a start-up material is problematic.
Once the oil goes, the idea of getting offworld goes with it.
There is no recovering for humans and there can never be a successor species to inherit the stars in our place.
Considering that no politician on the planet is even dreaming of preventing the catastrophic collapse of our city-culture, and that not one of the military dictators, priests or lawyers that control our countries would understand the problem never mind be able to create or grasp a solution this is not a matter amenable to any fixing.
When the oil starts to run out, wars will inevitably ensue. This will accelerate the collapse. The result will not look like a "Mad Max" movie set. It will be far, far more brutal.
So we may as well have another beer.