Most companies are indeed not willing to discuss these things. If your stance is "be able to negotiate these standard contracts or walk away" you will be doing a lot of walking away.

In a world where employees have even an ounce of power, this might change, but we don't live in that world. Even in the software world, what new hire has any power whatsoever to negotiate their employment agreement? You're at your weakest: You have no track record yet at the company, few to no allies, and there is a line of other applicants out the door who would be thrilled to have your job offer. From the company's point of view, why should they bother with you if you're already being difficult?