With so many of the population living for hundreds, if not thousands of years, societies tend to cling to tried and true ways of doing things.
Yet there is a constant drive from younger generations to find more economical and easier methods. In addition, Xanth has subtly guided the technological development of her Children since Elysia's? creation, determined that this realm will remain "pure".
For these reasons, and like many things in Elysia, technology is an eclectic mixture of old and new, familiar and alien. Zanaryans have harnessed elemental energy to fuel their society, but they refuse to give over such secrets to the other realms so Elysian scientists and inventors have turned to new and unique sources instead.
A general rule of thumb when considering Elysian technology is that the more pollutive it is, the less likely it is to exist or work outside of Earth?. While some small communities may get away with burning coal fires or oil lamps, it just isn't done on a large scale and there are much cleaner ways to get the energy they need. The majority of Elysians have never even heard of nuclear energy or guns, or technology of their ilk.