I just don't see why they think that women can't perform in combat roles. it's been proven since the War on Terror that there are no front lines anymore. anybody could have to fight.
The primary problem, I believe, is the same as women in any other role (military or otherwise) - the old boys club. It's the same reason there are fewer women CEOs, politicians, etc.
The culture is set up to exclude women as much as possible, and it is ingrained and reinforced from year to year, rather than any reform being made. It's hard to break the cycle, because the people that are in the positions to do so seldom want to, and those that the task to do so, have been doing what they've been doing for so long, they don't feel the need to alter things. It's an unfortunate case of the "if it ain't broke, don't fix it" mentality. Unfortunately, it is broke, but if they don't, or can't, see it that way, they'll drag their heels to avoid fixing it, or just assume that the person that steps into their role after they retire can deal with the mess. Unfortunately, the person that steps into that role has usually been trained by the person leaving it, so the cycle continues.
That's why I suggested that we attempt to change things as early as possible - early Elementary schools - so that, hopefully, the next generation that comes through doesn't have all the old boys hang ups (and it'd be nice if all the Victorian-inherited sexual repression was gone, along with the current rebellion-to-those-mores).
We'll see. The ADF is hoping to roll this out in 5 years, so it gives them a bit of time to lay some groundwork, and make some inroads. Ultimately, time will tell.