I work at Google, and when I started, I thought the idea of unionizing there is ridiculous.
They already have a very well defined leveling system. The promotion and hiring system - people hate - but it is as un-nepotistic as possible and (I think) fairer than pretty much anywhere else.
The compensation is already higher than basically everywhere - as you mentioned - ESPECIALLY considering expectations for your work.
And, sure, I think no one in America gets enough time off. We could maybe squeeze out 5 weeks of PTO for all employees.
Originally, I thought, is that worth unionizing for? I didn't think so.
HOWEVER, Googlers have since convinced me that this is more about employees having a voice in corporate decisions than compensation. For example (and I don't really agree with this) - most Googlers are VERY much against Google working with the DoD. They want to be able to use unions to block that. Others want to use unions to force Google to be more transparent about what it's doing with data and so on. Others want a better way for employees to speak up when we do things that seem illegal (breaking GDPR rules) or extremely unethical (hypnotizing babies on YouTube for ad-money). Currently, as with most companies, Google is a company that really cares only about maximizing shareholder value. Most Googlers were hired when the Google slogan was "Do no evil" and they really took that to heart. And for a long time, that WAS true. Now, a lot of them (and current employees) feel differently. And they think unions can bring "Do no evil" back to our main corporate guideline.
I'm not sure I'm convinced this is worth it or possible, but (to me) it's DEFINITELY more convincing than the compensation / working conditions argument.
If we unionizing and employees get a stronger corporate voice AND 5+ weeks PTO, I'll be very happy. But it seems like a pipe dream to me.