I never said that version 0.5.0 will be the last one. The game main story will end at version ~1.0.0, and the complete end of the whole game is scheduled for version ~2.0.0 plus dlc, you can read about it here (https://boosty.to/hvostt/posts/96778723-4c0a-4b39-af9e-e92f98d77175?share=post_l...).
As for Mama Sam, she will be bigger and the storyline will explain it all and you will get answers to those questions later on.