I seem to have a habit of making guesses around technology, on scarce evidence, which turn out to be right. Past guesses that I may not have written down before.
Anti-Ballistic Missile Defense
Back in the 1980s, when Reagan spent much money on the "Star-Wars" programs, I thought anti-ballistic missles defense was possible ... but very hard. When (late-80s / early-90s) read they were building the missiles too early, I assumed the program had failed.
Nothing since has changed that early judgement.
When approaching a very-hard problem, you have to divide the problem into series of smaller problems. (Call this divide-and-conquer, to which we should return.) Solve the smaller problems, and you can solve the larger problem. If you want to intercept intercontinental ballistic missiles, you start by intercepting tennis balls thrown across a football field. Then you scale up.
If the intermediate problems were solved, we would have had lots of intermediate products. Since no-one was (then) intercepting mortar rounds, I assumed the anti-ballistic missiles were a failure. (In case you think these problems are entirely unrelated, they are not. If there is no one on your staff to explain, that is a problem.)
Now as then, I believe this is a solvable problem, but not solved.
When Boeing announced in the late-1990s that they were moving their headquarters to Chicago, I thought that Boeing was in trouble.
I am an Engineer, but had read enough ... even then ... to know that a business that lost track of their core did badly. Boeing used to build great airliners (1950s, 1960s, and into 1970s). When the folk running a business start to think their core is making money, not making a product, the product suffers, and customers notice. Even folk in the business-literature seem to know this bit. There is a paid-fabric of excuses around Boeing, but cannot hide the core fault.
The current faults in the Boeing 737 can be traced back to bad choices made in Boeing/Chicago. (No. Not any of the offered distractions.)
Our best hope is to spin-off Boeing/Chicago from Boeing/Seattle.
The promise of railguns has always been to get more energy on target, and this was a hard problem from the start. Early railguns tended to self-destruct as stray energy destroyed the gun. So the big challenge was to control that stray energy (as clear in the 1980s).
When I saw the recent Navy video of a railgun with giant fireball, I assumed the program had failed.
Again, divide and conquer. There should be a series of smaller working railguns, before the larger. There is not any of the intermediate products, so we can assume failure.