Equal pay for equal work is a nice phrase, but this is not the way the world works. Forget gender for a minute, and think about whether this approach has a chance to work in any situation where we're trying to equalize economic outcomes.
You don't get paid just based on the work you do. The risks you take, your ability to negotiate, and your ability to leverage your existing finances can play a much bigger role in how much money you make than your actual work. This is why investors make more money than management, who make more money than the people doing the work.
This policy of focusing on salary, standardized benefits, and career development worked in the economy a generation or two removed from today. Now, wealth and advancement are generated through job-hopping or maintaining ownership of your work, not annualized salary. I think telling women they'll do well by sticking with one company and fighting for raises and career development is a recipe to create a gender wage gap.