The point is that most of these technologies have already reaped the cheap and easy, and, indeed, almost all of the hard and expensive improvements that are eve

The point is that most of these technologies have already reaped the cheap and easy, and, indeed, almost all of the hard and expensive improvements that are ever going to be made. In this respect, we are entering a period similar to the early twentieth century when we hit the limits to coal-powered technologies. The big difference today being that there is no even more energy-dense and easily available new energy source available to us to usher in a new suite of technologies in the way that oil-based technologies rapidly replaced coal in the years after World War Two. Disagree, we have at least two and possibly third sources of energy that can replace oil. Those being solar & wind plus nuclear respectively. Historically speaking it took large investments in drilling techniques and infrastructure to allow oil to replace coal as a major energy source. It isn't that different now.