It confuses me when the what if arguments call for the reader to accept as fact some historical failure scenario, be it the Concorde, British Airtours, Pac West, etc. etc. and then incorrectly interpret the facts to support a pre concieved justification for their action.
If the thread is to stick to engine fires and go-no-go decisions, then perhaps we could rule out discussions relating to ruptured fuel tanks where no fire bell was sounded. Remember that the best protection that you have to prevent an inflight engine fire from disabling the aircraft is the fuel shutoff valve to the affected engine. I don't think that you can statistically cite many accidents where inflight engine fires, within the engine pod system progressed to the point where they prevented the aircraft from flying. Your greatest risk is when the aircraft stops on the runway (including landing)