You're 100% correct, its all about $$$ pulling a tooth is around $50.00 a root canal around $1.500 or higher.
You wont get Insurance if you have a "pre-existing" condition. I checked it out because I did not want to pay cash for my two root canals.
You have two choices: Have the root canal done and pay big bucks or have it pulled IF the dentist is willing to pull it. I saw one who flat out told me "I refuse to pull a good tooth". Of course a root canal brings in more money.
I had one root canal done, and a couple of months later the tooth fell out. They will NOT give you a refund if your tooth falls out. I was told " I told you that my success rate for root canals are 80%, I'm sorry you fell into the 20% where it failed". Since his dental assistant was right there when he told me that his success rate is 80% there wasn't a thing I could do. She would have backed him up that she heard him say that, and I went along with it and allowed him to go ahead and do the root canal.
I switched dentists since, not because the root canal failed, but because I don't need to hear some dentist who is after big bucks telling me "he doesn't pull a good tooth" its my mouth, and my money, and MY decision, period. There are plenty of dentists out there willing to pull a tooth.
I may be incorrect, but I believe since you started treatment on this tooth that it would be considered pre-existing and not be covered by your insurance. And you dont want to fudge because insurance fraud is illegal. (as I am sure you know) If you are concerned about redecay, go ahead and have it done, ask if they will do payments maybe, or offer trade out, legal work for dental work. You never know, the dentist may bite. (Sorry couldnt help the pun)