* You don't just take your kids in to work with you. The Google daycares were not any closer to whatever office you happen to work in than some third-party daycare. [edit: they weren't particularly close a long time ago when Google was concentrated in North Bayshore, and then became even less so as Google's offices were spread out more and people bounced around more often, and then became even less so with wfh...]
* You can't actually get in. There was a waitlist and your position on it actually got worse over time (because sibling priority), then later a lottery system where you pay money to play but never win.
* From what I heard recently from a daycare provider (I can't directly verify), it wasn't very good if you did get in. The typical tenure for a teacher was like a month, which is shockingly bad. Like how do you screw up pay/work environment so badly that's possible? And their understanding of children's needs wasn't great either. For example, they organized the kids into rooms by age (which is common but not universal) and...had no transition period at all or hint to the kids that these transitions were coming. They were just in one room one day with one set of teachers, then unexpectedly in another room with another set of teachers the next, which was super confusing and alarming to them.
* It was supposedly subsidized but still strangely expensive. [edit to add: when I first heard about it, this was explained to me as a consequence of it having very high-quality staff who are paid well, but this doesn't match up with the bullet above. Maybe what I heard from the daycare provider was wrong. Maybe quality has gone downhill. Maybe it was never good. I think there are a variety of factors that would have allowed it to continue existing until now without ever having been good. An absolutely tiny proportion of interested people actually were able to try it. Those who did probably felt very lucky to get in and disinclined to complain/give up their exclusive spot, and folks on the waitlist disinclined to listen to their complaints... additionally, many of the parents who went there had never had kids in another daycare to compare against...]