Thanks for keeping this discussion going, lysergic.acid.
I agree with you on striking a balance with caution and practicality...risk/reward, and also that politics play a large role. The development of technology has far surpassed our rate of political development, which is very frustrating to watch unfold.
The reason I mentioned military aircraft design was because of the development timeline of a modern military aircraft. You mentioned the F-35, so to use that as an example: Much of the F-35 development came out of the 80's and 90's. Particularly, the short takeoff/vertical landing capabilities and conceptual development began as early as 1983. Further development and merging of programs (politically driven) occurred in the early 90's. Various test aircraft flew in the 90's to support the program and then Lockheed's X-35 flew in 2000. The A-variant should show up around 2013, B around 2012, and C around 2015 (hopefully). That's about a 30 year program right there...by no means quick, even if you don't count the first 10 years of development.
UAV development has been quicker, partly because they don't have pilots so if we lose them there are only financial worries. I think Lockheed lost the Polecat in testing not too long ago.
A side note on CAD: It is awesome, but still truly slow. The complex arguments we give it these days still take months to pump out useful information for complex designs on high-end computers. The problem is that they cannot optimize the designs for us...that day will come, though. Then we will be able to give a CAD program parameters and a desired outcome and it will spit out the best solution.