A lot of things have come together recently that make fusion a lot cheaper to pursue than previous efforts.
- Magnets have gotten way more powerful, this occurred to such a degree that you can take something as big as ITER and shrink it down to something that would fit in a small building (SPARC)
- Our ability to accurately simulate plasmas and fusion reactions have gotten us to the point where we can eliminate a lot of bad designs without testing
- Material engineering has improved enough for us to produce materials that can survive the extreme conditions within the reactor for longer
These and I'm sure there are more have reduced costs enough that taking risks on designs is wasting millions instead of billions. Now we're seeing a plethora of designs coming out that are relatively cheap to build and experiment with. There are so many going on right now that it's a reasonable assumption that one or more might actually achieve net energy in the next 5-10 years. The story goes once net energy is achieved that investment in the technology will take off.
Medium term I really hope somebody figures out aneutronic fusion, which produces little to no neutrons but instead produces positively charged ions and xrays which can both be converted directly into electricity. In theory you can power thousands of homes with something that fits inside a shipping container that uses abundant materials as fuel (Hydrogen + Boron). It might even be possible to shrink something down like this to fit inside vehicles! Having cheap near limitless power production could solve most of humanities problems and it's exciting that we're finally getting close to this being a reality.
Edit: The Aneutronic designs are also interesting in that they create a beam of energy that exits the device in a controllable direction. It's possible this could be used for thrust in space craft.
