A career break may happen to anyone by infinite reasons beyond motherhood. Most people have such career-pausing or career-delaying events (health issues, depression, fatherhood, taking care of an elderly relative), most conceal it, motherhood just happens not to be concealable.
And things don't change as fast. Not even in IT. And even if changed, legacy is always there, begging for someone to take care of it instead of going to the newest shiny thing.
People out of the market need some warm-up time? Yes, they do. Even machines need to warm-up, dammit.
What people should understand, is that the economy turns because there are mothers, fathers, and kids. I would be retired at 35 if didn't marry and hadn't a kid. Once upon a time I was buying a car, the saleswoman was worried about her job because of her pregnancy. I said "I am buying a new car because of the kid. No pregnant women, no car sales." (If I were single or divorced, would have a couple vintage cars.)