That's because flush toilets responded effectively to a real human need: how to dispose of human waste in urban areas. Once that problem is solved, further innovation is mainly wasted.
I expected a better pun...
What's problems are we facing that are as important as removing human waste from urban areas?
Let's see... Traffic fatalities, to become extinct within 30 years or so, as self-driving vehicles take over. Also will transform the transportation and urban landscape to unrecognizability.
Poverty is another one; but it's not like we know of a specific technological innovation that would solve poverty
You can't "solve" poverty, the distribution will always be there, it's statistical mechanics and probability at work. Not even the former soviet union, with no unemployment and with the standard of living near uniform, was able to bring up everyone to this admittedly low standard.
Maybe solving death and disease
"Solving" is a strong word. But cancer research keeps chugging along, with new ideas popping up at least as fast as before. Augmentation, miniaturization and automation is progressing well, too. The latter would be much further along if not for the many regulatory issues. Medicine is ripe for an industrial revolution, with surgical conveyor belts replacing master craftsmen and their apprentices.
Even if we had teleporters, would future Tyler Cowens be writing that they're not as innovative as the car - and would they be correct, in that a teleporter is just a more efficient way of solving a problem that cars and airplanes had already partially solved?
That's just silly, if someone claimed that. There is more difference between an airplane and a teleporter than between an airplane and a rickshaw. Imagine, no roads, no travel time, no humans clustering into cities and countries... Unfortunately, there is no indication that teleporting is anywhere on the horizon, we don't have any clue about the new physics that would allow that.
As for something as revolutionary as the birth control, responsible eugenics is getting closer to reality, and is held back mostly by the prevailing hypocritical morality.
I suspect that this OP is sort of a devil's advocate and you personally don't believe Tyler Cowen that the pace of innovation is really slowing.
You can't "solve" poverty, the distribution will always be there, it's statistical mechanics and probability at work.
Hang on, isn't that conflating (1) raising the minimum of the income/wealth/welfare distribution and (2) eliminating the variance of the income/wealth/welfare distribution? Poverty could still be basically solved by the first route (and arguably is being solved) even if the second route isn't realistic.
Cross-posted at Practical Ethics.
This is an addendum to a previous post, which argued that we may be underestimating the impact of innovation because we have so much of it. I noted that we underestimated the innovative aspect of the CD because many other technologies partially overlapped with it, such as television, radio, cinema, ipod, walkman, landline phone, mobile phone, laptop, VCR and Tivo's. Without these overlapping technologies, we could see the CD's true potential and estimate it higher as an innovation. Many different technologies could substitute for each other.
But this argument brings out a salient point: if so many innovations overlap or potentially overlap, then there must be many more innovations that purposes for innovations. Tyler Cowen made the interesting point that the internet isn't as innovative as the flushing toilet (or indeed the television). He certainly has a point here: imagine society without toilets or youtube, which would be most tolerable (or most survivable)?
But the flush toilet can only be invented once. We might have access to talking super toilets with multi-coloured fountains - but all the bells and whistles are less useful that the original flushing toilet aspect. That's because flush toilets responded effectively to a real human need: how to dispose of human waste in urban areas. Once that problem is solved, further innovation is mainly wasted.
This suggests that while we may indeed be plucking the innovation low-hanging fruits, it might not be because we lack a supply of innovation, but because we're exhausting the easy demand for innovation. What current needs do we have that we're waiting for innovation to solve? What's problems are we facing that are as important as removing human waste from urban areas?
There seem to be very few. Maybe solving death and disease: and we can make a very strong case that medical innovation is indeed slowing. Poverty is another one; but it's not like we know of a specific technological innovation that would solve poverty, if only someone would develop it. We might want easy access to space, or effective alternative energies: but the way people and governments spend their money confirms that this is not a top priority for many. Even if we had teleporters, would future Tyler Cowens be writing that they're not as innovative as the car - and would they be correct, in that a teleporter is just a more efficient way of solving a problem that cars and airplanes had already partially solved?
In summary, outside of the medical field, I don't see any conceivable realistic technological innovation that would be as transformative as the flush toilet, vaccinations, birth control, telephones, cars and airplanes. We might have exhausted the low-hanging fruits in our desires.
EDIT: some have suggested "high-throughput atomically precise manufacturing" as a general solution to material poverty, which would be an interesting counterexample.