As you pointed out, it's not that unusual to have long periods of stability. I've also seen breakdowns of how the vast majority of price movement has occurred in very short periods of time.

I don't think people are so price sensitive that these normal daily fluctuations would be a problem, even if they persisted. Then, every so often, major price changes would have to be made. That's an issue for long duration contracts, but it's fine for day to day expenditures.