Especially when not many people want to read a science fiction book where humanity gets quickly and completely wiped out by a superior force. Even works where humans slowly die off due to their own problems (e.g. On the Beach) are uncommon.
Especially when not many people want to read a science fiction book where humanity gets quickly and completely wiped out by a superior force. Even works where humans slowly die off due to their own problems (e.g. On the Beach) are uncommon.