We agree that it is oversimplifying to conclude, without knowing all the factors, that a particular experience makes one tool more productive than another.

Sure. Perhaps the increasingly creaky nature of your average VFP developer is its greatest strength: the wily old fox tends to prevail over the eager young pup. ;-)

I know some developers who could probably still be productive with assembler language and punch card decks.

I have a memory firmly fixed in my mind of an old Burroughs mainframe that booted from a long paper strip. Owned by some large corporate, it was obsoleted and sent to tender, attracting a single offer- from the university computer club for $5 and a six-pack. ;-) It was installed in the human sciences building where it was used to great effect by a group of us. Its best feature was its giant Winchester drive stack the size of a fridge. It kept blowing circuit breakers when we tried to start it, allowing us to create incredibly loud crescendo sounds followed by a power failure and pulsating slowdown. it sounded like a flying saucer trying to start. Of course we were gone and all evidence removed when affected parties investigated. ;-) Then one day a fellow called Darroch went down and held the circuit breaker, allowing the drive to reach full speed. The noise, during med school lectures, was absolutely indescribable and a tremendous pleasure. There must have been something wrong with the drive to cause it to roar and vibrate like that. Anyway, suffice to say the the room was "needed" shortly after that and the machine disappeared. Such is life.