One thing that I've noticed as I work my way through the ageing process:
Age 18 - 25: Going to the hardware store: employees would freely offer assistance. I never had to hunt down an employee to get waited on.
25 - 50: Especially when accompanied by young children: Hardware store employees would run in the opposite direction when they saw me coming. It was infuriating trying to get waited on. I often took my cute daughter with me, and would send her to find an employee. She'd go around the corner, and return with one hot on her heels in less than 2 minutes!
50+: Evidently, HS employees take pity on little old women. Once again, I am able to get assistance in a HW store without having to don running shoes and chase them down.
But, you're right: the way women are taken advantage of is totally infuriating, especially when it comes to auto repair or purchase. Once, hubby and I were looking for a car for me. He was along just to see that I didn't get shafted. Invariably, the salesman would direct all of his attention to hubby, even after hubby made it clear that this would be MY car, I would be paying for it, and I would be the one choosing it, and driving it. One particularly infuriating guy directed his entire pitch to hubby, even after being redirected to speak to me, until: Finally, he turned to me and pointed out what he thought would clinch the sale with me: "Look at this! This model has a lighted vanity mirror!" He smugly declared as he pulled down the visor over the RIDER seat!!!