This isn't always the case. I've watched people spend far more money on video shorts than I've spent on film shorts. Equipment houses will only do you deals on equipment that they know is unlikely to generate them any income while you have it. If you're asking for the latest high format digital camera kit you have to realise that everyone else is too. If, on the other hand, you like the look of the knackered Arri SR2 sat out the back gathering dust you might even be looking at a freebie.
Film stock is very expensive.
So is high format digital tape. The two are incomparable until you actually work out, based on someone else's experience, how much you will have used by the time you finish. No one's claiming it's cheaper to shoot on film, but it's cheaper than you thought. With film you have to have a very strict shooting ratio - the number of takes allowed for each shot against the running time of that shot in the final cut. With video you can be Kubrick and get away with it.