The total value might not be that much, but I believe that the fact that they are "together", the collection as a whole should be worth around that money (efforts for collecting, etc).
I don't think it works like that. The amount my house is worth is based on the number of rooms, the location and the condition, not the accumulated effort to build it.
So… it does work like that. The value of the collection and of your house is a combination of its raw value, as well as less tangible/quantifiable factors (location, condition) – not to mention supply/demand.
The accumulated effort of building your house – and thus the worth – is encapsulated right there in the number of rooms, location, and condition. In fact, I'd bet the human effort in building a house (planning, building, decorating) is more than the cost of bricks and mortar.