Well, as long as they can make electricity too cheap to meter, we can get helium from somewhere. Mine it from LNG sources currently untapped due to EROI < 1, or ship it from the goddamn Moon - ultimately, every problem in life (except that of human heart) can be solved with cheap energy.

The mere existence of proof-of-work cryptocurrencies means that it is impossible to ever have electricity that is "too cheap to meter". Any time electricity prices would fall below the price of mining, that creates a market opportunity that will be filled by more mining. Wasted electricity is the product.

With the trend of orbital launches becoming cheaper, it might be that mining helium off-Tera will be our long term supply. Especially if the alternative is adjusting the amount of protons in an atom.

There are several challenges, not least of which is storage. We have considerable leakage in most of our current helium storage solutions on earth because it’s so light. Our national reserves are literally in underground caverns because it’s better than anything we can build. Space just means any containment system will need to work in a wider range of pressure/temperatures.

There is to my knowledge no reason to assume that complicated physics experiments that heat water to run a steam engine will be much cheaper than fission power plants, unfortunately.