Sounds as if her career trajectory may have flat-lined - for a variety of reasons anyone as obtuse as she is not likely to last more than 3 or 4 years in any big city firm. Remember - big firms never fire an associate - particularly a female associate - they simply cease assigning any new work to the flat liner. At some point the associate, now twisting slowly in the wind, is reduced to begging partners for work and, that not forthcoming, leaves.
If not on a partnership trajectory after four years, you're right. However, some firms do let associates go--they call them in after a couple of years and let them know they are not on a partnership track and that they may want to look elsewhere.
vaudine