Why doesn't Dead Space 3 restart in the same place after I quit the game?
This is how the game is designed to work. When doing a save and quit, it saves your inventory (and presumably quest progress) but not your current location. Saving of the location you start at seems to be basically checkpoint-based in my experience.
If you just quit it will just save your inventory. Try checking if theres the save symbol in the upper right corner (autosave, which saves your location) so you know when you are safe to quit without having to start at another location again.