In the LinkedIn NGS board, someone posted an item about a review that either examines the remaining difficulties of nanopore approaches or makes them sound insurmountable; I'm not sure as I haven't broken through the paywall (a cardinal rule of this blog is it must not consume personal funds!). Did the publisher tart up a teaser to get more business? Is the author a creditable expert on the field (disputed in another thread)? Both really outside my scope. But, I do have to mildly object to a comment made in the LI board that "it just may be that nanopore sequencers are the perpetual motion machines or our age". We know perpetual motions machines just cannot ever work, but I think I know what the commenter (Tim Hunkapillar, who clearly knows a thing or two about DNA sequencing technology) was trying to get at: the risk that nanopores are a technology that can never quite deliver.
To me, a more apt comparison would be to the world of nuclear power, and the question is whether nanopores are more akin to nuclear fission or nuclear fusion. With the Manhattan Project, the United States pushed from the cutting edge of laboratory research to demonstrating the ability to execute either controlled or uncontrolled nuclear fission chain reactions. Less than a decade was required to go from the first controlled fission reaction to a prototype nuclear reactor (according to Wikipedia). Since then, nuclear fission has been an important, if troublesome, contributor to the electric power requirements of many nations.
On the other hand, despite a significant investment over more than half a century by multiple nations, no working fusion reactor prototype yet exists. Since I was a young lad watching Nova (and before!), the promise of energetic break-even has always been just around the corner. But that has never quite happened.
So nuclear fission and fusion represent two very different technological stories. Both looked like primarily engineering projects, with the science mostly solved. Fission (and Project Apollo) largely played out in the manner, though not without a lot of nasty (and sometimes fatal) surprises en route. Fusion's story is not over, but is in danger of never being realized. There is always a risk that a fusion facility would become so expensive to build that it would never make economic sense.
Will nanopores ever deliver fast, cheap sequencing? Are the seemingly constant shifts in direction, chemistries and such really necessary tacks required on the course for victory, or are they random wanderings that will never reach home? Or, perhaps nanopores will succeed, but only after becoming economically obsolete due to the advent of another sequencing technology? As is attributed to either Yogi Berra or Niels Bohr (or Nielsi Bohra?) , prediction is hard, especially about the future.