A lot of times it's better to let unhappy people take their unhappiness elsewhere. I've had plenty of experiences where employees wanted reasonable changes to salary, working arrangements, or equipment and we accommodated them. However frequently people are unhappy for reasons that won't be changing or make unreasonable demands, and since these people will never be satisfied anyways it is easier to let them leave and replace them with somebody who wants what you have to offer.

If companies don't do what you think they should then start your own, and if you're right you should be able to out compete them.