This analysis excludes geothermal and nuclear, which have massive energy potential. Yet even limited as it is, based on its assumptions, we could grow at these rates for centuries, at least, before having to worry about physical limits even within the solar system, so why fret about it now.
Focusing on realizing that growth now would save monumental amounts of energy from being wasted, as the sun radiates it into space, and allow trillions to live who otherwise wouldn't have.
Yes, growth is logically not going to continue forever. But we are nowhere close to the point that growth will inevitably have to stop.
There's a moral undertone here of course that that growth is coming at a price and that therefore we need to show some restraint. It's a very elaborate argument against energy gluttony. That's a particular world view that seems to never really catch on with the wider public. At least judging from their waste lines.
What does seem to happen is that we are rapidly transitioning to more guilt free forms of energy generation. For example, put solar panels on your roof and you get free kwh for your Tesla and you can turn your AC on as long as you want. Problem solved. That's a consumerist version of reality that is a bit more real in the sense that that is actually something that a lot of people aspire to do at a scale that matters.
Not all energy usage is bad. Energy production growth is fine as long as we do it sustainably. And now that that seems to become the default, the next interesting thing for humanity is to figure out what to do with all that clean, plentiful energy.
Focusing on realizing that growth now would save monumental amounts of energy from being wasted, as the sun radiates it into space, and allow trillions to live who otherwise wouldn't have.