Their incentive structure doesn't lead to longevity. Nobody gets promoted for keeping a product alive, they get promoted for shipping something new. That's why we're on version 37 of whatever their chat client is called now.
I think we can be reasonably sure that search, Gmail, and some flavor of AI will live on, but other than that, Google apps are basically end-of-life at launch.
It's also paradoxically the talent in tech that isolates them. The internal tech stack is so incredibly specialized, most Google products have to either be built for internal users or external users.
Agree there are lots of other contributing causes like culture, incentives, security, etc.
It's telling that basically all of Google's successful projects were either acquisitions or were sponsored directly by the founders (or sometimes, were acquisitions that were directly sponsored by the founders). Those are the only situations where you are immune from the performance review & promotion process.