I welcome WotC's attempts at trying to be more inclusive and I welcome them being explicit about it in the PHB. As a straight white male, I have always enjoyed a position of entitlement, however I'm no longer part of that plum 18-35 demographic. I recognize that I might often be blind to the struggles that marginalized groups might face and should as a person try to be more inclusive.
Growing up D&D was a haven for a marginalized group I was a part of though - bookworms/non-jocks/nerds/computer geeks/whatever - we welcomed whoever wanted to play, mostly male, but not entirely.
I DM for 3 different groups and I view the 5e gender policy differently for each group.
Group 1 - Friends and coworkers - 2 women, 5 men - all married, all straight - the women are spouses of other players, but are there because they want to be and enjoy the game. Any sexism or gender bias is not tolerated. If a player wanted to have a gay or transgender PC, it would be supported by me as DM, but I fear it would be an excuse to perpetuate stereotypes for the sake of (perceived) humor.
Group 2 - My family - PG rating, sexuality and sexual issues are not welcome. I go out of my way it include powerful female NPCs and villains.
Group 3 - my daughter and her friends (all girls) - again PG rating, sexuality is not really welcome. That would be creepy. I expect my daughter to take over DM duties and they can steer it where they wish. They also all plan to join the D&D club at junior high

I told my daughter that she and her friends
do not have to put up with any gamer-boy attitudes and I would be more than happy to volunteer if the club needed another adult. She came home super excited last week saying the first meeting was Friday and another girl (other than her group) signed up!
So, to the OP - Is the policy attracting new players? From my perspective, the game is certainly attracting more females than it did when I was a kid. More gender balance is a good thing. Gaming with my wife is fun, gaming with my daughter is fun, seeing my daughter get excited about the game with her friends is great.