The trade off is we spend that money on fossil fuels.
And therefore we spend the money on more air pollution, dirtier rivers, dirtier seas, more heavy metals in our soils and air, etc.
So the comic absolutely works even if climate change isn’t real.
The only argument that’s left is the idea that we may possibly spend more money on clean energy than we do on fossil fuels for the same amount of energy.
However, renewables are already on par with fossil fuels pretty much across the world, and their costs are dropping considerably, even if we do not consider climate change impacts. For example, in the U.S., which is particularly unfriendly to renewables from a cost perspective due to expensive labor, new solar energy is cheaper than burning coal in an existing coal plant (so without even considering the cost of constructing the plant in the first place).
But the comic undersells its message even further. Due to the fewer steps it takes to get electricity from the energy of the wind or the energy of sunlight to your outlet, compared to getting the energy of oil or coal buried underground to your outlet, the actual primary energy we need will be lower with renewable energy. So the actual cost will be even lower than a direct calculation of the current total energy supply of the world to meet the same energy demand.
Your concept works in theory. What it fails to recognize is that in the real world, the primary factors keeping fossil fuels around are:
1. The power of the dominant energy companies which are trillion dollar business and include massive governments who have bought politicians to ensure they do not get disrupted. 2. Status quo benefits. The fact that they are the status quo provides benefits like people not being as comfortable with new tech, and the grid and other energy transport systems setup for fossil fuels. For example, gas powered cars being the status quo have led to tens if not hundreds of billions of dollars being spent in setting up networks of gas stations, networks of roads to carry the trucks that move the gas to those gas stations, and the many tens of thousands of trucks that have been designed built and are operated to carry that gas around. If we were starting from scratch, it would cost a fraction of that money to beef up the power grid to supply that power to electric cars in the form of electricity instead.
Ultimately the comic isn’t just right, it undersells its case, and the only reason we keep choosing the worse tradeoff even if we don’t consider climate change is due to market distortions caused by politics and the fact that the trillion dollar companies who traffic in fossil fuels are way more politically powerful than the future renewable energy companies, which are just little startups right now relative to the fossil fuel giants.