Clearly Bradbury is suggesting that the role of technology in our lives will be what we allow it to be. The children are making what they will out of what the parents give them and then the parents grow angry that they have chosen to take something to an extreme that they had not visualized or approved. It is a relative constant in much science fiction that eventually technology can be used against its creators or providers in a way that they hadn't envisioned.
Perhaps the second theme is that of the fact that devices cannot actually take the place of "parenting," no matter how advanced or how seamlessly "integrated" into life. The lack of interaction between the parents and the children suggests that the parents have accepted the technology and their role as parents became secondary as they allowed the money and resources they used to buy the special house and the special rooms to take the place of the effort and work of actual parenting with all of its uncertainty.
In my opinion, what Bradbury is saying about technology in this story is that people in modern America (even back in his day) were getting to the point where they were relying on technology too much. My topic sentence for this would be:
In this story, Ray Bradbury argues that people are relying too much on technology and are losing some degree of their humanity as they do so.
I think that Bradbury is arguing that permissive parenting, parents who give in too easily to their kids, is a problem for society. My topic sentence would be
In this story, Bradbury makes the case that modern parents have lost the respect of their children because they do not try to discipline them enough.