Because the majority of the population always tries to copy the rich. Eating lavish meals with lots of meat was the norm in high society so now it's what everybody wants for dinner. A large manicured lawn was a show of wealth and thus everybody now wants their patch of well maintained grass, even in a desert. Flying and vacations on the other side of the planet was for the jet set so now everybody gets in economy class for holiday. Trickle down is also for habits, life style and consumption. They are the example to follow and should behave like it. It's the old concept of noblesse oblige.