The short answer is "no one." It exists as a result of thousands of years of first practiced, then inherited acceptable and expected 'business behaviors.' Women were leaders, peacemakers and collaborators in managing the home front, while men practiced timeless principles and practices in business, developing the current 'landscape for success.'
The wage gap evolved on its own.
The current context for success in business existed long before my mother in the 50's took on her first part time job for 'pin money.' Women only stepped into business full time a few decades ago. At the point where families became dependent on both salaries and divorce was on the rise, women were often forced to blend the roles together, being bother 'mother and father.'
Blaming conditions and circumstances is not the point.
Crushing the wage gap before predicted mid century is the point. Finding viable and multiple solutions to further slow the gap collapse is the point.
Women have simply been unaware of what it takes to match the current context for success in business. They are however learning. After 250 generations of not knowing or practicing known principles of success, why would we expect women to burst through the proverbial glass ceiling with such a lack of knowledge?
After serving in the corporate world for 50 years, I have observed how business is done from a number of perspectives. A dozen years ago I asked my boss, then a 34 year old, vice president and with MBA from Kenan Flagler, how was it that she -- a quiet, tiny woman -- operated so easily with men. Her answer was simple and I never forgot it. She said "I watch what they do." She matched the context for business acumen and success, so she was listened to and promoted.
If you look around, you will see that women stick out like a sore thumb in business. They are fish out of water, they hug, jingle bracelets, squirm in their chairs, put on lipstick in meetings, and tell the whole story when a few bullet points are all that is required to make their point. This does not match success in business.
Yet over our 250 or so generations of recorded history, women hugged because it was part of 'making peace.' There was no reason or time to sit still, and they had to often tell the whole story to diffuse altercations and maintain cooperation.
Blame it on the Monkeys.
Still want to blame someone or something for the wage gap? Why not blame it on the Snow Monkeys of Japan?
Whether you go along with the idea that behaviors practiced over generations eventually are inherited without any further learning, it doesn't matter. This is an explanation of how it could be that business context was crafted from certain behaviors and that they are foreign to women. It's called the "Hundredth monkey effect."
Stick your chest out.
One part for changing behavior to match the current context is easy. The other part -- the most important part -- is confidence. While woman can learn to match and mirror men on the surface so we are listened to and heard, building confidence is not an overnight deal.How many times have I observed over 50 years in business men stepping up to the plate to claim a promotion when they simply hadn't done the work or were not capable to begin with. Yet automatically they exaggerated to get what they want and they took it too!
Women, already uncomfortable in business, do not yet believe they are capable of business success and even more, women do not believe they are worthy or deserving of it. They won't stick out their chest!
Women are born leaders.
Managing home and family throughout history was no easy task. Women are expert leaders in family, in your community, at your children's schools, in church; just not yet in business.
Women have things to learn absolutely. And those that push through the barriers will be successful. Now it's time for business owners and leaders to note their automatic behavior in writing women off based on behaviors that are not 'comfortable' to them and start listening with intention. When women come to the table in business and are fully heard, optimum skills are at hand to solve problems and grow companies.