Wood is incredibly cheap if it is analyzed on a per square foot basis as a raw material.  Even though wood recently tripled in price per linear foot it still represents an inexpensive base material.  There are at least 2 major problems that need to be understood when initial "cheap" is the "chosen one":

1. Copious amounts of very skilled and therefore expensive labor is required to transform this cheap material into a useful building component.  Since there are literally thousands of individual wood parts required to construct a timber frame structure it should be no surprise that great quantities of highly skilled labor will be required to make a tree undergoing decomposition useful.  Not to mention the great efforts (house wraps, vapor barriers, tar paper, foam sprays) that have to be employed to protect same "inexpensive" components from moisture, fungi, termites and heat sources (fire).

2. When the wood assembly is completed this extreme labor investment in the component transformation is lost, that is the consumer is left with a decomposing tree that will rot, be eaten by insects and quite readily catch fire and quite possibly incinerate its surroundings.

The point is that all of the considerable money spent in transforming wood can be better invested in high quality, durable materials that will last for centuries and not cause fear or worries of premature loss to its owner/occupier.