You're correct about valuation, but the parent post was meant to address "how much liquid dollars should you expect to receive vs. 409a." You are likely to receive less in most cases (read: unless there are wildly successful public liquidity events) due to liquidation preferences.
Plenty of (non-VC backed) startups raise some money and then sell privately; it’s often the case that preference does not cause the common stock value to drop below the most recent 409a in these cases.
(In my experience, the 409a is on the order of 20% of the most recent raise, and preference is not more than 50%, in my area. And obviously you hope to sell for more than the last raise!).
