> And you need at least one real customer project to dogfood the platform initially. Because most platforms start out way too generic with pure architecture astronauts [0] at the helm.

The Rule of Three in Refactoring applies to this scale, too. If you are building a "platform" for one customer project, that's a one-off and quite possibly YAGNI. If you are building a "platform" for two customer projects, that's likely coincidence and still possibly doesn't show company-wide need. If you can build for at least three customer projects, that is a pattern, that provides real guidance on exactly how generic things need to be and better ideas how to abstract it.