Welcome to enterprise, stuff like this happens all the time. There's not a whole lot to be done about losing out to an alternate vendor based on an exec's personal recommendation. I wouldn't frame it as "what did I do wrong?", because there might not have been anything you could do to win that deal. This just happens sometimes.
The lesson is that relationships matter a ton in any enterprise play. It sucks in hindsight, but it never feels good to invest so much in a big potential client for it not to work out. And upfront spec work is, unfortunately, a common and necessary evil in the enterprise world.
Sounds like you were decently close to closing a whale, so that's positive. Clearly you have something that somebody wants, so live to fight another day.
The lesson is that relationships matter a ton in any enterprise play. It sucks in hindsight, but it never feels good to invest so much in a big potential client for it not to work out. And upfront spec work is, unfortunately, a common and necessary evil in the enterprise world.
Sounds like you were decently close to closing a whale, so that's positive. Clearly you have something that somebody wants, so live to fight another day.