If you go back quite a ways, I'm willing to bet at least some of the innovation-required Castles and Cathedrals and Pyramids of history were completed "on schedule" with it known up front that they would take many years to finish.
I suspect a lot of projects are accurately classified as 10-30 years away, given a certain level of funding and a dedicated team. Absent that, they may very well take twice as long or more. I always like to see what these long-term oriented institutions like SENS and MIRI say they would do if they had x times more money, to see that they've got a plan -- fortunately those ones do give that information.
The LHC was approved for construction start in 1995. The wiki article doesn't capture it but you can bet the science behind the design of the LHC wasn't all done the year before. It didn't achieve its first real goals until 2015.
https://en.wikipedia.org/wiki/LIGO
LIGO was dreamed up in the 1960's to detect gravitational waves. Took until 2002 to get the first one built big enough to theoretically detect them, and until 2015 to finally get measurements demonstrating the existence of waves.
Real science is slow. This "20 years means I don't know" business is indicative of perhaps not appreciating the difference between basic science and applied science/engineering. I know we're used to engineering projects pumping out new awesome tech every couple years, but basic science is hard and takes a long time.
I picked the word "technology" instead of "science" on purpose. Science isn't slow or fast; it can't be predicted at all. Technologies; different story. Someone says I'm going to build you a piece of technology and it will take 20 years, that means they don't know how to do it. There are no exceptions.
Precisely. Take fusion for instance:
This is the source of the "joke" that fusion will always be 20 years away. It's because it's been grossly under-funded ever since that prediction was made.
What are these three experiments? Which of them have already been done in the existing plan? And what others might need to be added?
Also curious is the expected total cost. Eyeballing each plan average cost and multiplying by the duration, the total costs are 6x14=84, 4x17=68, 3x22=66, and 2.5x29=72.5 billion dollars. The accelerated and aggressive plans are more expensive than the moderate plan!
I suppose there's some additional overhead costs associated with keeping the program running for 29 years instead of 17, but I would have expected all the rush orders, overtime, and extra staff to make the faster programs much more expensive.
The problem is that for every person who says, "This is 20 years away", there are unrealistic people who are saying, "This is 5 years away". And there are pessimistic people who are saying, "Oh, this is just going to go on for ever. They don't really know how long it's going to take".
Will you ever be able to read popular news articles and reasonably expect the predictions to be accurate? I doubt it. Are there people in the world who have a pretty good idea how long it will actually take? For a great many things, yes.
Slightly more on topic, it's the thing in my home that most makes me feel like I'm living in the future :-)
I'm very skeptical when people do 20 year predictions from the current state of the art into something which is impossible to do today for any amount of money, such as this quantum computing based RSA breaker.
Short answer : over 114 years from 1714, Britain sought and paid rewards for accurate measures of longitude. Resulting of course in the invention of 'modern' clocks.
For sure. Government-promised highways, for example.
Oh, uh, wait a minute...