What happened to innovation?
I found this quote interesting: "There are a decent number of people working on more efficient jet engines, but not very many civilians working on replacing the jet engine with something new."<p>It's not really the problem that there aren't very many people working on replacing jet engines. The issue is that the problem domain is full of physical limits. Ask yourself: why are we still using quicksort now, half a century after it was developed? Well, because theory tells us that any sorting algorithm based on binary comparisons is going to require at least O(n log(n)) such comparisons, and that is going to remain the case no matter how much engineering effort you throw at the problem. All you can really do when it comes to sorting algorithms is improve on the constant factors and take advantage of special cases (radix sort for small integer items, etc).<p>Software engineers don't usually have to think in terms of theoretical limits. But when I was in engineering school, as an aerospace major, every course began with: these are the theoretical limits in this particular area--all you can do is approach them more closely. A Brayton cycle has a certain efficiency at a given pressure ratio and an airfoil has a certain maximum lift-curve slope and there is nothing you can do about it. Improvements are in "hard engineering"--new materials that can withstand higher temperatures and pressures to eke out slightly more efficiency, etc. You're already seeing this in semiconductor manufacturing. As you run into the limits of lithography with ever-smaller wavelengths of light, semiconductor fabrication plants get exponentially more expensive to build.<p>These physical limits are what give the traditional engineering fields the shape of their "innovation curve." Much more happened in aerospace engineering from 1930 to 1960 than has (and will) happen from 1960 to 2020. The long-hanging fruit is gone, and all that's left is hard engineering.<p>And of course, this all plays into the "get rich quick" issue the author brings up. If you had a billion dollars lying around, where would you invest that money? A jet engine that's 0.5% more efficient? If you had $100 billion, would you spend it making an alternative to jet engines entirely (in an industry where people will fly on truly shitty airlines just to save $5 on a ticket)?