When wood as it comes from the tree is not exactly what we want, we modify it. Modification includes things like drying, sawing, gluing and so on. Further, there were some old processes for modifying wood (and a few new ones too) that changed the properties. We have wood that has acetic acid added (Accoya-TM), wood that is heated (torrified; Masonite is a heated product), wood that has chemicals added such as polyethylene glycol (PEG), monomers of styrene or other simple chemical that form a polymer within the wood (example is the hard wood-plastic knife handles), and wood that has various wood preservatives added to prevent rot (decay). Sometimes we add water repellants. Cement and wood are combined (HardiBoard-TM), and sometimes metal and wood are laminated or combined. And sometimes various wood species are combined (for example, plywood or laminated veneer lumber [LVL]). Certainly, there are other marriages of chemicals and materials.
Wood for years ago had natural decay resistance that is better than the wood grown and harvested today. Trees were larger and older, providing different material. Oftentimes, the structural use of wood was not considered to be for centuries, but rather for decades or even less (for example, log cabins were usually temporary, or short term, housing). So, today, the consumer demands have changed. (Example: I am changing four windows in my home that have rotted after 23 years.) Finally, I have seen architects and designers using wood and wood products in situations were other, wood or non-wood products could perform better (such as for house siding).
The bottom line is that if you can define the properties that you want in wood, there is a wood species or wood product that can furnish those properties.
Terrified wood is indeed one of those special products that has different properties and that may be a good substitute for "natural" wood.