Yes they did. Because they do not care about a good browser engine product. They care about selling services on top of that. So whether it's Chromium or something else entirely, they don't care. They went with what had the most external developers working on it because again, they do not care about the engine.
>So they should start small and slowly build up the artificial complexity that accumulated over decades in incubent browsers until it reaches feature parity?
No, they should find a new angle. What are they building a browser engine for? To go back to the burger example, you cannot compete with McDonalds by trying to do everything they do. Everyone understands this about general products, you can't compete with Apple by making an iPhone clone. You can't compete with Marvel by making funny light hearted hero movies. Yet, when it comes to browser engines people short circuit.
Do you know about Steam? The video game launcher/store. This store is so successful that it's spawned many competitors who struggle to compete. Why is this? Because they do not want to change the status quo too much, they just want their company to be where Steam is. So they spend so much time and money trying to add features Steam has had for years now, all while people refuse to budge because "why use a steam clone that's worse?" Sound familiar?
This is the current problem with browser engines. Everyone just wants to be Chrome, to have Chrome's userbase, but they don't want to actually think about a product. They don't want to find a niche, or make people rethink what a browser should be/do.
Therefore, it's not a problem that people keep failing to be Chrome. I say good riddance. We don't need a Chrome alternative; we need something else entirely.