So only one person instead of two has to suffer through a dreadful commute, you need only one car instead of two, one parent works close to where the kids go to school, etc. If you live in the middle, everything is far away for everybody.

That doesn't mean it's not viable to live in the middle, but I think these are some pretty good arguments why it's often preferable to live close to at least one partner's workplace. Obviously it's not going to work for everybody, but if you're thinking about where to buy your house, this may be worth taking into consideration.