What you are describing is called a "mirrorless" camera which is what the article says will be the future. They also have interchangeable lenses, but there are

What you are describing is called a "mirrorless" camera which is what the article says will be the future. They also have interchangeable lenses, but there are less constraints on the design since they don't have to interface with another optical system, just the digital sensor, which is the main point the article is trying to make.