Without a Mr. Clueless X in the way, it would be presented as your fault that the company lost suchandsuch major deal by not already having the feature. That's a much harder political game to play.
My own job is to basically read all the docs and just point out some documentation that tells the higher up that this is not a good idea, or this feature is not likely, or draw diagrams explaining the complexity of the feature. The programmer who is doing the work can't do this, because it will sound like an excuse. And the analyst is also there to help higher ups figure out whether the developers are just giving excuses or saying something true.
If that isn't happening then you should probably get out, as things won't get better.