I agree, 20 years ago nobody would have ever believed that we would be able to send gram-scaled nanocrafts to proxima centauri at 1/5th the speed of light. Our technology is evolving at a superfast pace. Ofcourse a Dyson sphere is much more advanced than that but I wouldn't be surprised that we could actually build one somewhere in the second half of this millenium.
RE: Could Humanity Ever Really Build a Dyson Sphere?