Ok, but is that true for GCP? The GCP portfolio seems to be intentionally run differently than products elsewhere within Google.

Looking at that list, there's not much of a record for GCP products. I'm just skimming, maybe Chatbase but I believe the plan was always to integrate it into Dialogflow itself.

Visited that site expecting to see Google Reader, Talk and some more. Turns out its pages upon pages of services, most of which I never heard off.

Is Google really just throwing stuff at the wall without even a thought about "what if it will stick"?

That's the sense that I get talking to anyone that works on new products at Google (GCP or otherwise). It seems like they just throw multiple teams at the same problem, see which one they like the most, and then sunset the others.