I think you're underestimating the levers people have to pull.

Yes, maternity data is lucrative, but such petitions and protest have a cost. E.g. Facebook already pays a decent premium to hire new (tech)workers because people see it as a resume black mark.

Working at a company while knowing that your work gets people endangered if not killed, well, that's pretty indicative you lack a sense of professional ethics.

And while companies have long not given a damn about professional ethics in tech, a lot of them are starting to wake up to the fact that "will casually endanger and screw people over for money" also applies to the company.

and the pregnancy data is too valuable to give up.

For Google their main issue is they've been bleeding their "best and brightest" workers; The ones who work on the most important and secret parts of the search engine and ad-markets. People who can walk out over such a disagreement and walk straight into a new job.

The ads are profitable, but not that profitable.

Google will probably try to compromise by adopting a policy that they won't comply with law enforcement requests seeking abortion data.

While I don't think you're wrong in that Google will likely still try the stupid approach first, but it'll cost them dearly and they'll change properly not short after.