Now, I don't expect politics to allow sharing of fusion energy to help other countries.
You are very wrong. ITER is a $20B international collaboration to construct an energy positive fusion reactor. The participants, including China the underwriter of the experiment detailed in this thread's article, are very much sharing.
It's probably not that easy; the reactors are extremely complicated and expensive to build, and I'm sure operating them isn't cheap either.
And the one thing I haven't heard much about yet is the yield - how much energy can it generate vs how much will it cost to run.
I don't think it'll be economically viable. I'll be happy to be proven wrong though.
I don't think current designs like the one discussed here will be. But I'm hoping it will lay the groundwork for much more useful reactors in the future.
But yes, the first ones to 'crack' the problem will have a head start in the commercial fusion power plant market, but I don't think it will last very long. As you say, most of the research is being published, and even if somebody manages to initially keep that final 'dot on the i' secret, it wouldn't take other researches long to figure it out.
Whilst a 20-30% reduction in energy cost would be great. The really important change is that it is much more scalable and easy to get. You don't need to dig up coal, or drill for oil. All of which can be limited. With a working fusion reactor a country like Singapore can be energy independent, in a way it never could with any other type.
This independence would mean no more need to mess around in areas with these resources (think middle east) or have your countries energy rely on a third party you'd rather not rely on (think Germany and others and their reliance on Russian gas)
[0] A Piece of the Sun: The Quest for Fusion Energy - throughly enjoyed this book.
For instance, it is chemically possible to combine water (either atmospheric or from a normal water source) with atmospheric CO2 to chemically synthesize hydrocarbons. It just takes energy. So you could have a single, absolutely massive fusion plant next to an atmospheric fuel refinery and use the hydrocarbons for fuel storage and distribution. You could do likewise with hydrogen and oxygen if you wanted to make fuel cells or rockets. And this would probably be cheaper than refining fossil fuels. You could actually run OPEC out of business this way, make the electric car obsolete, make airlines carbon-neutral, etc., etc.
Climate change? Just extract the atmospheric CO2 using cheap fusion energy and turn it into an easily sequestrable form. Nitrogen fertilizers? You can make those from the air too. Drought? Use fusion power to run desalination plants. Arable land becomes a non-issue with fusion because vertical farming becomes easy. Every city could just grow whatever they needed in exactly the right climate conditions in a set of enclosed vertical farms, though they might not need to because energy will be so cheap that there's no problem shipping the stuff from Honduras anyway.
Computation scales with power, too. More power, more computation, except computation produces heat, which you need even more power to chill.
I do disagree with you on Hydrogen fuel cells replacing electric cars though. I think battery powered cars will be better than hydrogen powered ones. The power storage is more reliable, and the power transfer is more simple (lines as opposed to truck delivery or pipeline. And if we assumed that it would be done on site at stations, then they would already have power lines, so just use that!)
Not what I meant to imply. You’d just use old-fashioned hydrocarbons, except reconstructed from atmospheric CO2 and water.