Retirement rules for industry versus worker

Often in recent years I have heard news stories that say "X "industry is taking away or changing health care of their retirees.
It is my position that if the employee has to make choices that he is not allowed to change after signing his or her retirement papers ie whether the spouse has survivor benefits.
In this case if the spouse dies and the employee remarries and wants to allow this new spouse to receive the benefits they cannot do it.
If industry won't can't allow you to change your decisions then they should not be able to change your retirement package after you sign the papers.
You have made your plans based on the known facts that you expected to happen.

I feel that federal law should prohibit this from happening.