One is always hearing about restaurants that are going "downhill." One seldom if ever seems to hear about any restaurant that is going "uphill." The best outcome seems to be to remain static, and that seems mostly to happen with good ol' homestyle local places serving some local type dish(es).
Is there a law of nature at work that almost always makes restaurants go downhill after a while, or is it just our perception (perhaps after getting used to, and then bored with, whatever made the place be "uphill" to start with), or is it something else?
Why is it that, on average, the trend always seems to be down?