What has that got to do with energy dense rocket fuels for getting to orbit ?!

The key phrase was "successor civilization".

So? We build nuclear power plants and it's not exactly easy/efficient to extract uranium. Hard things are done all the time.

Having coal/oil is pretty irrelevant in terms of whether a civilization can build spacecraft.

"and when we drain the planet dry of easily-accessible fossil fuels we’ve deprived any successor civilization of its opportunity to escape the planet."

Successor. Whoever comes along after we've done ourselves in.

Huh? "We" is the human race, whatever civilization. What point are you trying to make? What I said stands, exactly how I said it.