Wind is readily available… easy to harvest and renewable. So is water now that we understand energy storage and transport via electricity were at most 100 years from restarting modern civilization.
You can't build and maintain those technologies without a ready supply of energy, and more importantly energy storage and distribution (which is MUCH more expensive and complicated for renewables).
And we don't have that yet. Every step of getting renewable energy from its source to the place where it performs work still depends so heavily on fossil fuels that we simply won't be able to survive without it for many decades to come (perhaps even centuries).
Losing our ability to extract fossil fuels at scale within the next 50 years would basically spell our doom.
