I have lived for many years within the energy budget provided by photovoltaics and the wind. It is possible to live well under such circumstances, and to be as technological as a city dweller, but first you have to eliminate the waste.
Take, for example, your houses and apartment buildings. They are so poorly constructed that the planet would be considerably better off, despite the waste, if we tore down every single last one of them and rebuilt them for longevity and energy efficiency.
A few buildings (maybe three in a city of 5 million people) are constructed well. They use (at the moment) ICF techniques and they are so well insulated that, even in the coldest days of January, the heating system can fail completely for over three days BEFORE ANYONE NOTICES that it is broken. They can use geothermal heating exclusively both winter and summer and provide complete comfort for 10% of the normal cost.
But you do not build your stuctures like this because energy efficiency is not a priority; money is the priority. The scumbag builders build shit buildings to maximize their profits; the scumbag realtors sell units to the ignorant masses for a fortune, and nothing changes.
What is wrong with humanity is that we are just too fucking stupid and far too much in love with ourselves to do the reasonable thing. We are crazy for money and it has become the arbiter of all success. Instead of killing off 90% of the species, we could begin by simply eliminating the 90% of our activity that is wilfully wasted and continue to live well, so long as the reduction in resource usage was not simply an excuse to increase our already ridiculous numbers.
So that is my alternative: stop being monsters. Otherwise I cast my vote for us all to die of a virus incubated in the backstreets of Shenzhen, and good riddance.