I'm so sorry you had to go through all that just to get an answer. After over 40 yrs, I still don't have an answer for that one. Haven't had it often, but when it happens, its devastating. Tried fungicides to no avail. Quarantine the affected ones & prune away the bad somewhat worked, but not as much as I would have liked. Like Shovel said, if you've found a cure, please share. Since blossom end rot for tomatoes is caused by a calcium deficiency, it did occur to me to add more calcium should I have it again, but haven't had it since I made that decision, So I've not had a chance to test that out. To go so far & have that happen is an emotional blow. I'm so sincerely sorry.