>This brings me to a different question: How likely is it that this sort of situation really happens? Namely, that the client insists on the software being programmed in one particular language, or (perhaps worse) in ANYTHING BUT one particular language.

That is a good question Hilmar. I would add a little to it. How many professions are out there where the professional must follow what the client wants instead of what he believes should be.

Do we go to the Doctor and tell him that the machine he is using for the ECG is obsolete?
Do we tell the engineer what are the best materials to build the supporting column of a building?
Do we tell the electrician that the brand of isolation tape He is using is no good?
Do we tell our accountants which brand of calculators should they be using?
Do we tell our arquitects which CAD program should be using?

Shouldn't we, as professional developers, provide the client the software he requires regardless of the language used, as long as it complies with all client specifications? Why would us accept the pressure from the client on which tool should we be using?