Yea, folks were a bit too optimistic early on about this stuff. Look at solar power technology, we discovered that effect way back in the earlier half of the 19th century, couldn't put it to commercial use until like, the 60's or 70's on calculators and other crap, and only now are we actually able to produce viable, large scale solar devices for market use.
Even atop that, the reset time for the research is crazy, considering you need a decade to build a new power plant to try out new theories and developments from the last one. I'm really not surprised its taking this long, we're just biased by the lens of recent developments in much simpler relative things.