George and Lydia Hadley are parents in name only. They acquired the Happylife house with the expectation that it would take the work out of family life. What they don't realize until too late is that they have gradually given all responsibility for raising their kids over to the house, and have become completely disconnected from them. As they have no active role in their children's lives, they have no place in their affections. They have been rendered superfluous, or worse, inconvenient when they try to interfere with what the kids want.
'The Veldt' isn't a condemnation of all modern conveniences, but rather a warning about what can happen when we let these things displace our personal relationships. Frances Bacon said that money is a good servant but a bad master. The same could be said about technology; it has many advantages, but we don't have to look very far to find examples of people who have allowed themselves to be controlled by it. The Happylife house isn't evil in itself: the trouble is caused by use without wisdom,guidance, or limits. One of the excuses that Lydia gives for not caring for her children herself is that the house can do it much more efficiently... she can't compete. But what's efficient isn't always what's best, especially in a family. Kids are hard work: needy, messy, and exhausting, and most people aren't born with perfect parenting skills. The answer though, is not to avoid responsibility, but to deal with it- even imperfectly- strengthening the bonds of family rather than becoming detached from it. No amount of technology or convenience can replace it, or compensate for its lack... as George and Lydia discover just a little too late.