I can't think of one instance in the 61 years I've been involved in photography when the price of film has gone down, so don't hold you're breath folks.
Maybe not in absolute terms but relative to wages and salaries I am sure that there were periods up to quite recently when film prices fell relative to income. Then came the quite sudden and dramatic rise in both film and paper from about 2007/8 which was put down to dramatic increases in material prices, the silver price being cited as the main culprit. As I recall it this was certainly the substance of Simon Galley's post on prices.
With a drop as large as this I wonder if we can expect to see Simon posting anything in this thread?