Guess what though ... good looking Inca/Egypt/Aztec/Mayan/Atlantis themed games do sell.
Key word there: "good". If I did Inca/Egypt/Aztec/Mayan/Atlantis it wouldn't be good. To do those well, you need to be an artist, and I'm not.
I know my limitations and I stick to things I can make less of a hash of ;)