'640K of memory should be enough for anybody.' - Bill Gates (apocryphal, apparently he never said this)
When the Jones' are using their energy-sucking teleporter to travel instantly to work and taking summer vacations to the Moon, when their kitchen is fitted with exotic self-cleaning metamaterials and they tolerate no natural discomfort in their lives, I would think that their neighbors would not be caught dead one step behind them. You can achieve happiness with less - but you can achieve happiness today with much less than your number as well, and most people measure themselves against their neighbors, not some theoretical absolute level of energy usage.
Energy consumption in the developed world tends to increase.
According to OurWorldInData[0] the number is closer to 220 kWH/capita/day, although it does show the usage as stable or even declining over the last decade.
According to the US Energy Information Administration[1] total energy usage seems to have increased. That particular chart stops at 2009, but this tool[2] using their data shows 1. stable usage since ~2007 and 2. roughly 10% increase since 1995, and a 3-fold increase since the start of the data in 1950. By a long time, did you mean since 2007?
[0]: https://ourworldindata.org/grapher/per-capita-energy-use?tab...
[1]: https://www.eia.gov/todayinenergy/detail.php?id=10
[2]: http://physics.bu.edu/~duffy/HTML5/climate_change_historical...
But there is a limit.
Current growth rates need an exponential increase in resources.
Even if we -after some technological singularity- could expand a sphere of influence that brings everything in the expanding bubble to complete subatomic level of control, this would mean at most sustainable cubic growth (available resources are growing cubically).
Not exponential growth.
World population is stabilizing, and, indeed, going to decrease. Now what.
I think his main most valuable point is that the status quo can't - and that stands.
Personally chasing constant growth doesn't sound like what we need to be aiming at anyway.
It would be saner to be engineering some long term stable state that we adjust as soon as new potentials become available.
Like aiming at a fixed upper limit maximum human population on earth with an acceptable minimal standard of life as opposed to letting blind growth search out the natural feedback loops instead.
This actually makes me lean towards saying that the economist is right, money is arbitrary anyway so if the argument is actually that the economy can increase forever I see no reason that can't happen physically. It's not real, it can't be real in the future and it's barely real now.
Our money system does need endless growth just to function properly but it only needs endless nominal growth. If inflation is high enough then real interest rates are negative. No need for real growth.
See also: 2000-watt society
I believe heat pollution would only become an issue once we start using several orders of magnitude more energy than we do now.