Are aliens broken or is it my game?

You can have someone in the scientist career as they level up in the career there will be more aliens. You can also build the Rocket ship and install the Wormhole generator which will give you the opportunity to visit sixam with plenty of Aliens talking with them will make it more likely that you see them in the streets. Remember that in many cases they will wear their disguise in the street so you may have a tough time recognizing them as being alien.