Do acqui-hires go through the same rigorous hiring process as regular hires at Google? I wonder how many engineers that are hired as part of an acquisition would actually pass the infamously hard interviewing process at Google.
Where it will really hurt Google is not so much acquihires (where you're doomed otherwise, especially without other options), but when there's any competition. Taking 75% as much money overall but having a great work outcome for everyone for the next 2-6 years is probably worth it, especially if you ever plan to do a startup again.
Which is sad, because Google sounds like an amazing place to work (your concerns for early-career people might be valid, but for senior people, people in infosec, or people at Google Labs, it sounds awesome).
If you are running out of money and don't have a choice, then your employees are probably going to be rolled into an existing product, and at that point, there's probably not a lot of benefit to Google to hire sub-par employees, so they may not get an offer or might get less than in the above case.
It also depends on what your team does: A failing company that does hard core research and employs a bunch of Phds might be worth a lot more than a random social startup that just employs a bunch of randos.