The problem with that metaphor is that ABC asked for the blueprint after they started construction. For starters, the show was rushed to pilot, it was the most expensive pilot episode ever at that point, and it wasn't until the pilot was being filmed that someone at ABC realized that no one had any clue what this show would be like a few seasons down the line, or even by the second episode. ABC execs were afraid the show would end up mired in mythology like Alias was at the time. So Lindelof and Abrams wrote this document to make ABC happy, but never intended to follow it. According to Lindelof, "By the time we started breaking the first two episodes, it was already very clear to everyone in the room that the document that we had written to get the show picked up was going to be completely and totally null and void."
"Run! We'll figure out why later!"
But why were they able to get away with it? Because of the average 15.69 million viewers per episode during the first season. Because the first season won an Emmy for Outstanding Drama Series. Because from day one, Lost was a cultural phenomenon that happened just as we collectively discovered that we can use the Internet and DVRs to obsess over TV shows. When you're a hit, the backstory of how you got to that point doesn't matter much to network executives; just keep up the impressive ratings and the executives will let you write your magnum opus as they dive headfirst into their Scrooge McDuck swimming pool of gold coins.