In what ways has the house infantilized the Hadleys in "The Veldt"? How does Bradbury depict this as dangerous?

George and Lydia's Happylife Home plays a number of roles in the story -- not least, it can be understood as the true antagonist, the force that undermines their parental authority and drives a wedge between them and their children. It has "infantalized" the parents, no doubt -- but if the parents have been turned into children, then it makes sense to ask what sort of "parent" the house can be. If you think about it that way, you can begin to see the shape of the satire at work in Bradbury's story. 

First, the basic thing about the house is that it does everything for you. The Happylife home is the ultimate expression of the labor-saving device: the home that "clothed and fed and rocked them to sleep and played and sang and was good to them." Lydia feels unnecessary, as you say: "That's just it. I feel like I don't belong here. The house is wife and mother now, and nursemaid." She wants to take a "vacation," which, oddly, means a return to domestic drudgery: she wants to be the one frying eggs, darning socks, sweeping the floor. 

Lydia's desire to do these things comes from her sense that the house has replaced her as mother; her assumption that "darning socks" is what makes a mother is of course another expression of her infantilization. Lydia longs to "go back" to being a mother, but it is clear that, in real terms, she doesn't know what that means -- cooking breakfast is not the same as having a emotional bond with your children, and, of course, that bond is exactly what is missing.

Second, the house satirizes the "leisure first" lifestyle Americans value to this day. The fact that the house will make dinner and tie your shoes is, on the face of it, a ridiculous exaggeration. But Bradbury is also indicting a society that confuses freedom from chores with freedom from responsibility. Perhaps the real reason George and Lydia are unhappy in the house is because of what it doesn't do -- absolve them of guilt for not connecting with their children. 

Third, the house infantalizes the parents in that it becomes the means for their children to assume the role of "head of household." That is, the suggestion is that the kids have hacked the house somehow (Peter may have "got into the machinery and fixed something"). George, who admires the technical acheivement of the house, really has no idea how it works. Lydia is childishly afraid of the nursery ("Those lions can't get out of there, can they?" she asks at one point). The parents fear the children, and fear that they have become more powerful than they are. 

Of course, the children become more powerful than the parents. That's what kids do: they grow up. I think, in the end, the house infantilizes the parents because it shows that the parents don't know, really, what being a parent is: someone that helps their children grow up. In the end, the house provides on last labor saving service: it gets rid of the parents altogether.