His ultimatum approach is an admirable one, and could definitely work for he and other actors with similar star power.
Of course, not every actor is as in demand or has the clout of Benedict Cumberbatch.
An actor with less name value and more in need may find himself without a job if he gives such an ultimatum.
Benedict Cumberbatch is also living up to his feminist ideals by using his new production company SunnyMarch (which is made up of primarily women) to back female-focused dramas.