Science

... over the decades.

Sometime over a hundred years ago Senators wanted to close the Patent Office because they thought everything had been invented. Around 1900, a professor proved that heavier than air (not balloons) machines would never fly.

And there is currently NO "stagnation in technological development".

In any case, even if our current knowledge of physics is the limit, that does not stop discoveries in biology or technological development. And it most especially does not lead to nihilism. If we have to live with our incredible cars and planes and internet and robots and music and movies we would be just fine: well cared for and well entertained.

If there are no warp drives or "replicators" the human race will not fall apart. That Varney dwells on Star Trek technology speaks volumes about the limitations of his imagination.

Logically, lack of progress on extremely complex problems does not mean progress is impossible.