Indeed, well characterised, though the solution isnt geothermal.
The solution can be found by taking your analysis a little further.
If we look at what drives profit, what it depends on is capital. To compute profit we have to have two capital amounts; what was paid out vs what we got back in return.
The computation becomes invalid if one or the other terms is either infinity or zero.
So profit only means something in a world where all things are considered as capital.
So the energy source has to be effectively infinite, and what we have to pay out, has to be zero in terms of Joules.
There is only one source satisfying that criteria, the sun.

Another way of looking at it is by noting that life requires a supply of Joules to continuously create everything we know. Those Joules come from the sun.

Whereas we remove Joules from Earth, consuming those to support only the life of humanity. Even if we donate some of those to other animals and life we depend on in our immediate environment, the net effect is still us removing Joules from Earth, at a greater rate than they are added, and therefore from all of life, including us. It is an incredibly inefficient process, in terms of Joules put in, for the Joules we get out of oil, for example. How can we even start to calculate the amount of Joules that went into creating a gallon of fuel, created over millions of years? But all we get back out is a few hundred KWh, and some pollution.

This is why it amazes me to hear folk trying to argue that solar energy is somehow inefficient, or insufficient to support humanity. Compared with extracting energy from Earth, well there is no comparison. Effectively infinite energy went in, whilst we took a tiny bit back out, but in the process we destroyed what was created by effectively infinite energy.

Geothermal, is energy from the core of Earth, which we should accept is residual heat only, remaining from when Earth was created. There is no work being done by the constant pressure of gravity on the constant mass of Earth, nor any other ongoing magical source of heat generation within Earth, so there is no generation of more heat, it is all simply heat stored in Earth from long ago. When we take any of that, we reduce the core temperature by a calculable amount. Over time the effects of that have to be cumulative, and for sure it won’t be a change benefiting us, or any other life. Again, all we are doing there is extracting energy from finite stores on Earth, and the net result is reduction of the Joules on Earth needed to sustain all of life.

So also from this point of view, it is obvious we need to use the energy of the sun, to pay back what is effectively an energy deficit to our planet, the same kind of energy deficit as paid back by any plant drawing energy from Earth until it first forms leaves. It pays back that deficit many thousands of times over, after it starts to accept the Joules of energy coming from the sun.

We just have to do the same. We already started to sprout leaves in the form of solar farms all over Earth.

Now all we need is for money to be issued on it, instead of money issued only as debt, which can only translate to promises to do the labor of extraction.

Solar energy requires no extraction, so can’t be represented by money-as-debt.

It can only be represented by money issued for free, because the energy is issued for free.

Issued like this, would be us mimicking the action in plants carried out by nutrients. The leaves of the plant convert the solar energy received to nutrients, and pass it on to all needing it, all of life on Earth.

That might sound difficult until we realise we already saw it, and the effects of it when 4tn stimulus was issued per month in US, oil prices went negative, and our planet saw the only spike of environmental recover ever. By then we had already been collecting solar energy and putting it to use at the rate of many GigaJoules per second, for a few years, so the latent value of the energy represented by 4tn per month stimulus was already in the US economy.

That was proof, and a demonstration of the world which awaits beyond profit.

We will see it again when inflation, and sheer people-power forces free money to be issued again, but this time we need to ensure it is left on, after being switched on, and we need to use some of it to complete the job of solar collection facilities implementation, backed up and distributed by hydrogen technology, to 100+ percent sustainability.

Then we will be paying back our real debt as a species, the energy debt we owe to our planet.