They should solve the problems, instead of hiding the symptoms. They need to encourage women to enter tech field. This could be done at school level. They could ensure that women don't face harrasement at work. They could help women find jobs after a gap due to childbirth.
Find why women don't take admissions in STEM as much as men do. If there isn't any human-made reason, then let it be. Don't force equal numbers down the throat of deserving candidates.
What is currently going on in the world isn't going to solve the problem of race/gender based problems.
I think all these suggestions could help. But it seems highly unlikely that a single company (even a powerful one like Google) can categorically solve the problem through these methods.
The reason I asked about your view of feasibility here is that you seem to be arguing that Google (and others with diversity preference in hiring) are making the wrong choice. But the alternatives you seem to favor are not a real choice Google could execute. It's not like they thought about massively altering the perception and delivery of STEM education to all kids, figured out an effective affordable method to do that, and then just did diversity hiring instead because the VP of HR felt like it.
You could certainly make the argument that there's a better choice they could make, or that their apparent choices are doing more harm than good. But right now you're comparing against an impossible straw-man so it's hard to take the argument seriously.
Find why women don't take admissions in STEM as much as men do. If there isn't any human-made reason, then let it be. Don't force equal numbers down the throat of deserving candidates.
What is currently going on in the world isn't going to solve the problem of race/gender based problems.