I worked for a company that used Common Lisp (though I didn’t write much myself). My coworkers were in general quite skilled and very smart, but they were not 100× more productive simply because they used Common Lisp.
100x more productive than who/what. Productive doing what? Are errors or bugs considered in the model of productivity. It’s pretty easy to make relative claims without any stated reference point. I’m 1000x stronger .