Google is a big company and maybe this was true but it feels false (having worked there & other large tech companies) that the reason for failing to get that project going was the lack of a PhD. Now having top engineers on board probably is key, but again that isn't tied to any advanced degree but due to Google hiring & promo committees which are intended to reward merit.

The value of this is multi-faceted. It shows technical validation by trusted engineering talent. Those engineers are able to expend their own political capital on the project. Those engineers have demonstrated an ability to navigate corporate hierarchy and deliver large-scale projects. One of the key requirements of higher levels of promotion is that you are focusing on strategic goals for the companies rather than strictly complex/important technical products.

Having interesting & exciting conversations is nothing. Everyone is smart & happy to nerd out about complex and interesting abstract concepts/designs. Doesn't mean that they think those ideas are worth pursuing or that they're worth pursuing right now.