I've been hearing this and similar arguments since I started college way back in 1986 and think it's just an indicator of laziness on the professors' side. Especially in engineering or sciences, it's really easy to write tests and requirements for papers that make cheating almost impossible. But recycling the same questions and the same term papers year after year and decade after decade makes it very easy for students to cheat. And this hasn't changed materially for at least 25 years. At my university, the student government had been keeping all tests and exercises since the founding in 1969 in three ring binders, so you just walked in, paid a small fee and copied the entire semester's materials. The only difference nowadays is that you can copy and paste, so students save a few hours retyping topics or copying them by hand. And one of my professor's argument that if students copy solutions, "They have to at least read it." is completely bogus in my opinion--I've taught enough labs classes to know that you can copy stuff without retaining anything.
But updating teaching materials, varying values, or just putting in actual calculations would make it easier for students to just do it themselves rather than trying to fix apply all the changes. It does require commitment by the professors and TAs, though. And obviously, copying stuff from the smart guy in class is still the preferred way of cheating.
Unfortunately, recycling tests and term papers and then trying to catch cheaters is not only pointless, but also detrimental. One of the things I had to teach newly graduated programmers for 15 years now is NOT to reinvent the wheel all the time. They are so conditioned not to copy anything that they not only search the internet for already existing code, some are even reluctant to use standard libraries. Obviously, this is not just a complete waste of company time, it also introduces hundreds or thousands of bugs, inferior implementations, and highly unmaintainable code. Libraries and other peoples' code (TM) are not perfect, but in most cases, it's good enough and better than what you hack up on your own with less than a couple of years of production coding under your belt.
So seriously academia, just stop whining, get off your butt and work on writing good tests instead of recycled assignments that facilitate copying and pasting.
Just as background, I run software planning for a $3bln+ company....