What you said re moats might be true but can't actually be concluded from the Tailwind story. Traffic to the funnel dropped by more than half. That easily explains their problems, and says nothing about moats.

Tailwind had a solid funnel and a good product. Now they only have a good product. That's enough to kill a business.

If (or more likely when) Google loses money because LLMs are replacing search, that's a story about moats.