Extreme Makeover Home Edition

I have a confession to make, I love Extreme Makeover Home Edition.  Granted it's a rather silly show.  It's organized the exact same way every time, aside from the family (that obviously changes every episode) you see one episode you've seen them all (kind of like a Bollywood film but that's a totally different ball game).  I love the idea of giving a family in need a house.  However, there are some things that I have always worried about.  First of all, finances.  It seems like there are some episodes where they end up paying off the mortgage and others where they don't mention it.  I would like to think that the episodes where they don't mention it the reason is because the family didn't have a mortgage to pay to begin with and therefore they are just being given the house for free.  Does this then mean the construction team is designing and building the house for charity?  Also, what happens to utilities?  Several houses are net zero houses where the house has solar panels, rain water collection areas, etc so that the utilities are already paid for.  But there are houses where this isn't the case.  These houses must have utility bills that are much higher than what the family is used to paying for.  These financial questions make me wonder what percentage of families who have been on this show still have these homes?

My second issue is with children's rooms.  Children's rooms in these houses are often totally decked out.  The kid loves trains, for example, so they design a train in the middle of the room with a child's bed built into it.  Only problem is the kid is 5.  The kid isn't going to be 5 forever.  So what happens when the child grows up?  Why not make a room that is a little more suitable to growing children, like the parents rooms tend to be?

Finally I am concerned with these houses in relation to Not So Big House (which I know I have been discussing a lot recently).  Many of the families on this show are large families living in small spaces.  They share rooms, often times with many individuals in the same room.  When the design team comes along and builds the family a new home, they often design one where every individual in the family has their own room.  This astounds the family as they've often never had their own room.  However, I believe this could also cause a psychological problem.  Now they have a house with rooms that are not used, and can go long periods of time (unlike the old house) and not see anyone.  This could cause problems of loneliness.  So instead of building such a large home for the family why not build a functioning Not So Big House, which would be much more suitable for the family and probably cause them less culture shock (moving from the old to new house)?