My skepticism isn't based on the specifics of any particular approach. Fusion in the sun has a containment vessel 850,000 miles in diameter. Scientists believe a star must be at least 80,000 miles in diameter to produce fusion temperatures and pressures (
Size of Smallest Possible Star Pinned Down). We need a containment vessel capable of continuously maintaining fusion temperatures and pressures like those in a star but of a tiny, tiny, tiny size. This seems like a very, very, very difficult problem.
All but one successful fusion power experiments have consumed more power than they produced and were of an instantaneous, not continuous, nature. The one exception that produced more power than it consumed took place last year. The very slow rate of progress is very convincing evidence of the extreme difficulty of the problem.
Generating more power than consumed is just the simplest problem, but it's a prerequisite for the more important and even more difficult problem of creating a self-sustaining fusion reaction. If it's taken 50 years of research to obtain more power than consumed just once, how long might it take to produce a self-sustaining fusion reaction? I believe it will be a very long time and be too complex to be economically feasible.
I don't think this should surprise people. Many things that are technologically possible are not economically feasible. Right now another form of energy production is on the verge of becoming economically infeasible, hydrofracking. Oil has only to drop another $10-20 per barrel and that will be the end of hydrofracking for the time being.
--Percy