I see what you're saying, and while I agree that indeed, unions are basically always adversarial to the employer at some level (every?), that doesn't mean that every employer or industry needs to prioritize unions on their list of things to be concerned with or counteract.

To take my argument to its logical extreme, let's imagine the real world probability that an asteroid may hit BigCo HQ and completely destroy its main data center and most of its key staff, killing the business both figuratively and physically; while that possibility is extremely remote, it's still a non-zero probability. Is it a good use of time for BigCo's execs to come up with a plan to lobby the government to build a giant laser to obliterate incoming asteroids? Would any individual bother? Probably not, because a more likely an immediate threat to BigCo is competition from other BigCos and even SmallCos, government regulation and so forth.

In comparison, if a particular company or industry happened to have such a culture where everyone was generally benevolent, everyone was making lots of money hand over fist, and the work-life balance was optimal, then it really doesn't make sense for big wigs to seriously consider dealing with the possibility of employees taking collective action to gain leverage because the will among individual employees may not exist. Maybe it'd manifest as a topic during a meeting between big wigs only to be shrugged off and replaced by the next agenda item.

On the other hand, if BigCo realized that something is creating a high probability that its employees will unionize, which is adversarial to BigCo, but the thing that is generating said will to unionize is too ingrained and there's no incentive for leadership to change it, the path of least resistance may be to develop techniques to persuade employees not to take action that may be in their own favor.

Indeed, unions can be bad for both employers and employees. That doesn't really matter, though, because either enough employees are going to believe they will benefit from a union or not, despite whether that becomes effectively true, and businesses know that unions are bad news for them; the business also couldn't care less whether a union is bad for their employees unless that hurts productivity by-proxy, as is the case with your example with talent attraction.

All that rambling is to say that I believe that all the individual pros and cons of unions can be presented and weighed, but ultimately the primary driver that creates the will to unionize comes from just how disgruntled or alienated employees feel. If employees don't feel alienation, if they feel they are treated with respect, they like the work they are doing, they are paid fairly, and can go home without stress at the end of the day, then what's the incentive to unionize? So that I can give yet another boss a slice of my paycheck that they didn't earn? Rather than think about all that, I'd rather just hit the gym after work, go home and not harbor that stress.

This is why I make presumptions about life as a Googler in a general sense. If being a Googler is the kind of career apex it at least once was seen as, it seems odd that those who have "made it" would think they need to spend time and money on unionizing. And why would Google's solution be so tactical? My guess is that there are reasons why Googlers in particular would want to unionize, that Google knows this, and have decided that the best way to address the issue is to weaponize psychology. Otherwise, it wouldn't be such a secret. Hell, they actually hired a company that specializes in this.

I could be way off base because I've never worked for Google, and having worked for Apple I'd presume that there are divisions of Google that operate significantly different from the others. Nevertheless, I still think it's reasonable to see a relationship between the employee experience and whether unionization is a real threat to a business.