Actually, a lot of people [erroneously] ascribe “the perceived deficiencies of a deployed system” to some deficiency of “the (whatever it is ...) programming language that was originally used to implement it.”   And... they perceive that “the solution to their problem” is “to rewrite it in <<insert_language_here>> ... And-d-d-d-d... they delude themselves into supposing that this step is anything less than:   “utterly and completely rewriting it.”   From Scratch.

They seem to have no trouble attaching “business risk equals zero” to such a hair-brained scheme . . .

Well, here’s a very-comparable (I think ...) real-world analogy:

False Syllogism #1:

• “This (“fifteen-story, full of offices and people”) building Sucks™.   (Premise.   Given.)
• This building is made of Wood.
• Therefore, the reason why this building Sucks™ is because it is Made of Wood™.

False Syllogism #2:

• If this building were not Made of Wood™, then it would not Suck™.
• Concrete™ is not Made of Wood.™
• Therefore, if this building were Made of Concrete™, it would not Suck.™

False Syllogism #3:

• The costs (and risks) of replacing a (“fifteen-story, full of offices and people”) Building Made of Wood™, with an equivalent Building Made of Concrete™, are negligible.
• Concrete™ is categorically-better than Wood.™
• Therefore, we should start immediately.

If we were talking about “an actual building,” then your damned-fool plans would never get off the ground.   The building-inspectors would stop you, if no one else did.   They would know perfectly-well that the only connection between a wooden structure and a concrete structure is that the before- and after-structures would coincidentally occupy the same real-estate lot, and they would prohibit you to think otherwise.   However, the computer-programming industry is ... at this point in time, at least ... “un-regulated and un-professionalized.”   Thus, at this point in time, “anything goes.”   Million-dollar mistakes like this one, therefore, happen all the time, because the folks that “pour the bits” imagine that they have nothing at all to learn from the folks that “pour the concrete.”   (Or, for that matter, that “erect the wood.”)

Maybe this particular project was built in a place where wood construction never would have been suitable.   (In the real-construction trades, such plans would never have been approved.)   But most likely, someone simply wants change for change’s own sake.   And, with no third-party voice of reason to check him, he sets sail.   Straight into:   “the same old rocks.”