I can only shrug and say, "De gustibus non est disputandum"

Beware this piece of cached wisdom.

I merely wish to emphasize that even catering to people with bad taste and questionable morals requires what we would call writing skill; not everyone can do it

True, but there may be a low-hanging-fruit effect: it could be that Rand's literary skill is much less of a factor in her success than the fact that she was in the right place at the right time to meet the thitherto-unmet needs of a certain audience.