Some Savannah kittens conform more closely to the breed standard, they are more sought-after and the price reflects this.
If the breeding cats were selected as the absolute best then that breeder probably paid “top dollar” for their cats and might expect the same for the kittens produced.
Sometimes there is an element of “you get what you pay for.” A kitten that is not as typey might be priced lower than its littermate that is amazing looking. Remember that this does not mean the personality of the kitten is different or lesser-quality, and if you are looking for a pet then the blackest of black spots might not be as important as an outgoing friendly disposition.
Of course, this doesn’t necessarily mean that a kitten that is priced high is necessarily the “best” kitten available, just that the breeder is asking a premium price. Buyer beware – do your research and ask enough questions to know that the price is fair for that particular kitten.