The problem with winning something like that is most certainly the taxes, and due to laws they cannot pay the taxes on it for the winner, as the winner would then have to pay taxes on what they used to pay the taxes on the house, etc.

If they truly wanted to make it something that the winner could afford they could make winning something like winning a lifetime lease or occupancy of the house, with the studio keeping the title to the house. Then all the winner would have to pay taxes on is the annual value of the lease.