In truth, the commercial exploitation of Mark Twain, within limits, both
testifies to his cultural power and continues it. Clemens did not make
Twain an icon of America on the strnegth of his literary talent alone,
but by strategically manipulating his public image. But when an image
becomes public, power over it belongs to the public. That's why the laws
on libel differ for public and private figures. You can use a picture of
Madonna to sell magazines or stories about her to sell books, but not to
sell cola, at least not without her permission.
If a group of interested parties somehow managed to reclaim Mark Twain's
image from commercialism, the result would in time reduce Twain to the
same cultural influence as Howells or James: important to readers and
scholars, but not iconic to Americans as a whole. We need Twain
cavorting around the Starship Enterprise to buff up his significance.
The appearance on StarTrek hurts his reputation for less than reducing
his importance to the culture as a whole.