Why is humanity investing so little on fusion research? Optimists expect fusion industry to be a reality in 2080 to 2100. Fusion means clean and unlimited amount of energy, it is the fuel of the universe. Fusion will solve most of our time problems including climate change and clear water supply. 
However the humanity global investment on research on fusion is around 40B\$ (around 20B\$ just for the ITER project). Beijing Olympic Game alone costed 40B\$ and the global wealth created per year is around 82.000B\$. Apple, Amazon, Microsoft and Google are worth each 1.000B\$+.
I understand that obtaining energy from fusion is, after 60 years of research, still a major scientific and industrial challenge with uncertainty. But last decade progress have been real. 
2080 is far too late. Why not invest say 1.000B\$ on 20 years and get a real chance to counter climate change before it is too late? Why not consider fusion as the new man-on-the-moon challenge? Most of us feel concerned by climate change, why so few realize the potential of fusion?
 A: There are a long list of reasons why more generous funding is not forthcoming; I will recount some of them here. 
First, there is a general distrust of nuclear energy, following the long history of disappointments surrounding atomic fission reactors. In a sense, fusion has a bad reputation because of fission, at least in the eyes of the public and most of the people they elect to high office. 
Second, as long as the USA is awash in fossil fuels (specifically, fracked natural gas and tar sands) there is little short-term economic advantage to funding a full-court press for fusion power. Getting the people who control funding to think long-term has always been and will continue to be a big problem. 
Third, there are many problems related to making fusion power feasible that our best efforts for over 60 years have not solved- not because we haven't spent enough money, but because physics conspires against us. One such problem for example is how to convert the kinetic energy of the neutrons given off by fusion into heat that can boil water and drive turbines in what is called the "first wall" of a hypothetical fusion reactor, without destroying the integrity of the material forming the first wall with the neutron flux. 
Finally, note that when governments subsidize sports into international spectacle, it makes sports enthusiasts happy quickly relative to the timescale of the expenditure. Those same sports enthusiasts cannot be made happy with progress in achieving breakeven in demonstration-scale fusion reactors, and until we can figure out some way to accomplish that, this situation in unlikely to change. 
