Some people can.
It is certainly possible to make beer at home that is every bit as good as the best beer you can buy. Having said that, homebrewing is not just about getting the best quality product any more than gardening, baking or home photography are. For these reasons, I think that homebrewed beer can be, and often is, more enjoyable than any beer you can buy. Some can, some can't but it doesn't matter much. The process is more important than the drinking.