1) Hand wavy "who will support this?" arguments. Sometimes with a prefix of "when you leave, who will..." etc.
2) Extreme top down management style "all innovation comes from above, even if that results in none at all". Often closely tied with credentialism. "we pay engineers to innovate, so shut up and do what they say". I interned at a place like that decades ago, now out of business.
3) Empire building / contractual obligation. "We paid a zillion bucks for lotus notes, you will use it, I don't care if it makes things slower than simple manual processes or your new ideas, we will use Lotus Notes anyway"
It is also because the business is run by lawyers, accountants, underwriters, and actuaries, and they have almost zero knowledge of software.
And, yes, actuaries. I mean you. You write terrible code. Terrible, terrible code.
It is thought that these niche languages are more productive in the hands of an expert, but then, you need an expert, which is scary for the corporate bottom line. Hence the mass adoption of Java to keep workers interchangeable.
Thankfully a few companies have realized what Jane Street did: niche languages actually make hiring easier if you are looking for top talent, and of course, the productivity is better too.
Related: http://flownet.com/gat/jpl-lisp.html
"The management world has tried to develop software engineering processes that allow people to be plugged into them like interchangeable components."
Know this guy? http://search.dilbert.com/comic/Mordac%20The%20Preventer