Health is an example of something that we’re trending towards. Cigarette use has declined hugely since the 60s because people learned how awful they are for you. The only thing that separates McDonald’s from cigs is that McDonald’s is cost efficient, and cigs are the opposite.

Regardless, if McDonald’s doesn’t clean up their act to be at least moderately not-horrible-for-you, in 50 years they’re going to be struggling, if not gone. Low-cost, healthy, and decently tasting alternatives will become available, and when the parents start taking their kids there instead so they don’t become obese, McDonald’s will lose that brand awareness and life-time loyalty they have with children. Once that first generation of non-McDonald’s goers grows up, they’re going to need a radical change.

I’m probably 100% wrong, but those are my thoughts.