Also, why is Tolkien's estate seemingly twiddling its thumbs while all these companies use its intellectual property? Or does the estate get licensing fees?
They have no claim, unless you create another literary character or something in the likeness of the original character. Naming a company after a fictional character is not an issue.
This status doesn't necessarily give the owner absolute control of the mark, but it can limit the ways in which others use it in trade.
Things would be this way whether "Sauron" was ever the name of a fictional character or not. The use as a character name by the trademark owner neither implicitly enhances nor diminishes the trademark's integrity.
Yeah, I have a feeling rebranding might be in their future. As one of the somewhat rare crossover people who are both technical but with some marketing chops, it never ceases to surprise me how branding can elude some people who are technically brilliant.