Might be worth remembering that companies like Google have significant links with education systems, so they can address their hiring not just at the "who is applying" stage.
Also, regarding "lowering the bar" - remember there is a lot more to building a SWE team than finding people who can do the best whiteboard coding challenges. Coding skills can be improved, diversity of backgrounds is also a team strength and one that can't be taught.
So, one would hope that by forcing hiring diversity now, companies 1) force the white dude monoculture to break down, encouraging 2) more women to see SWE as an appealing opportunity, making 3) their future hiring pipeline and hiring committees sufficiently diverse that they don't need to force numbers.
Also worth remembering that women CS grads entering the field used to be climbing at the same rate as lawyers and other similar fields, then something changed in the mid-1980s and while the other fields progressed ever-nearer 50%, CS numbers took a nosedive. I don't have good research into exactly why that happened, but I'm guessing women didn't say "oh we're doing 32bit computers now? Nah you keep this one bros" ;)
Also worth remembering that women CS grads entering the field used to be climbing at the same rate as lawyers and other similar fields, then something changed in the mid-1980s and while the other fields progressed ever-nearer 50%, CS numbers took a nosedive. I don't have good research into exactly why that happened, but I'm guessing women didn't say "oh we're doing 32bit computers now? Nah you keep this one bros" ;)