But the problem is not technical in nature - it is social. The question of who decides, and how is the decision made, to issue more currency and distribute it, or to obviate existing currency - this is a political(-economic) question.
Yes, and that is exactly what the essay is about. Crypto proponents will only be able to overcome that issue, under capitalism, if they solve the issue of a fixed money supply. It is not sufficient to solve the computing issue if it leads to massive inequality and concentration of wealth, as well as other problems.
As long as it requires work by CPUs or GPUs it is for rich people.
Gold requires actual physical mining equipment and labor.
You could make the argument that gold is also for rich people, but no one seems to have a problem with it.
Many people object to gold being used as money. Now that gold is mostly for jewelry and investment people can afford to not care about it.