>>As I see it happen, there are two motives that can drive management to switch:
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>>1) They have new goals that require new features in the language/platform. Features that are (still) missing in the language/platform they already use. They hear of another language or platform that actually offers those features and decide to switch. (Sometimes to reluctantly switch back indeed, after significant failures.)
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>>2) They are forced to switch, because 1] further development of the used language or platform is bound to cease, and 2] their company policy does not allow the use of technology that is no longer supported by the vendor.
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>VFP is officially supported by MS until 2015. There's no sane reason to feel like VFP has to be dropped straight away and apps rewritten.
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>Your first point is more pertinent. If the language can't do what you need as the technology is now too far out of date, that's when you should start thinking about rewrites or at least, rewrites of portions of existing apps.

Oh yes, there IS a sane reason to feel forced to switch in case 2.

A) A complex system is not (or only seldom) built with a short lifecycle in mind. Such a system is planned to be operational for at least 10-15 years. Escalation procedures almost always demand that the language provider too must be able to eventually provide support.

B) Long before that kind of (escalation) support stops, development of the language stops. Continuing development with such a language implies that there will be no possibility to benefit from newer features as offered by other languages that are continuated. Some of them may prove to be essential for modernization and for business strategy.