The distance to energy production through fusion is better expressed in funding, less so in time.
Unfortunately, it's from 2012, if I understand correctly. Can anybody recommend a similarly braod discussion of the big questions for the 'simple (wo)man'?
I think the burden of proof should be on the scientist, it just doesn't seem plausible to me that fusion progress is so fungible, especially not at timescales less than what it takes to train a fusion researcher.