To write badly on a really epic scale, however, is very difficult. Mere illiteracy does not suffice; a poorly spelled and grammatically weak piece of writing only tires the reader. The best examples of truly bad writing I've come across (Eye of Argon is a notable exception) go beyond this level; their writers could write relatively correct, unostentatious prose if they tried, but this isn't enough. They want to be Profound, to be Serious Writers, to write Great Narrative. They struggle mightily with a task that most of us would never attempt, and their reward is the mockery of generations of readers.
An interesting case is Amanda McKittrick Ros, whose work was "admired" by such twentieth-century luminaries as Tolkien, Aldous Huxley, and C. S. Lewis. And one can easily see why; no ordinary writer would think, for example, of the following opening line, from her novel Delina Delaney:
Have you ever visited that portion of Erin's plot that offers its sympathetic soil for the minute survey and scrutinous examination of those in political power, whose decision has wisely been the means before now of converting the stern and prejudiced, and reaching the hand of slight aid to share its strength in augmenting its agricultural richness?I don't have a clue what this means. But you get the impression that a great deal of effort went into crafting it, and you almost feel bad for so churlishly failing to understand it. And try as you might to emulate it, you quickly realize that such bad prose is incredibly difficult to craft. Witness the Lyttle Lytton Competition, which since 2001 has challenged entrants to write the worst possible opening line to an imaginary novel. Some of the entries have been very good, but most are unconvincing - you can't imagine a real novel beginning that way, or the prose style makes it clear that the author is a good writer trying to be funny.
The only musical analogue I can think of is the Waltz from one of Stravinsky's Suites for small orchestra. This is a rare example of successful, purely musical parody; a little band playing almost impossibly banal music, with a trumpet player who can't seem to count.