I sure do miss those wonderful Golden Arches I grew up with, though. Why in the world did McDonald’s have to change that theme beloved by millions? Why did they have to alienate their customer base? Why did they tamper with what clearly worked? And their price increases! Why can’t we get 15¢ burgers any more?

My guess is that the Golden Arches were relatively expensive to build and maintain and came to be seen as unnecessary as the chain saturated the marketplace and became universally known. Local zoning and signage laws also became troublesome.
Moreover, although McDonald's pioneered fast food, they have had to deal with competition that impacts their business model at many levels. And we can't get burgers for 15¢ any more for the same reason that a solid middle class home can no longer be had for $40,000. Land costs, higher taxes, greater regulation, rising wages, and population growth all contribute to higher prices.