Sorry to hear it. While it may be difficult to do, an eggtopsy can provide a lot of useful information. I think that if it had been scrambled to begin with, you probably wouldn't have seen as much development as you did. Was it a shipped egg? Early quitters are fairly common with eggs that have...
You may be right, if the veins are disappearing. 🙁 It hasn't quit until it's obvious that it's gone...you should have a better idea of what's happened in a few days.