A key point they made is that formal methods, as currently practiced, have a cost-benefit curve that is very hockey-shaped.
This doesn't really mean that the cost isn't worth it, but rather that it's hard to demonstrate the cost-effectiveness in a small pilot.
It also means that the pay-off is fragile. Because apparently a lot of things need to come together for the value to show.
It also means that the pay-off is fragile. Because apparently a lot of things need to come together for the value to show.