I'm only saying that technology did not change hugely even in Europe between the dawn of the Iron Age and about AD 1400, ca 2500 years.
This is simply not true. Technological development was going on around the world all the time, even in Europe. For example, in the years leading up to 1000 AD, Europe experienced an agricultural revolution. Developments such as the iron plow and horse collar (imported from asia, actually) replaced technologically inferior Roman farming methods, leading to a massive increase in agricultural output across Europe.
An even bigger myth is that lands outside of Europe were unchanging. China was actually a land of constant change over its thousands of years of history. The Hand dynasty was very different from the Tang dynasty, and so on. Practically every Chinese dynasty has its own list of major inventions as well.
The problem is that people often overlook a whole host of categories of invention. People rarely talk about developments in engineering, agriculture, metallurgy, etc. as much as they like to fixate on sexier inventions like the compass or gunpowder. But these kinds of technological development are in many ways more important, and they were occurring throughout history, all around the world.
An excellent example of technological progress in Europe can be seen in architecture. Castles first began to dominate Europe in the 9th century, and changed radically as the Middle Ages progressed. Huge developments can also be seen in cathedrals, such as the development of Gothic architecture (which involved overcoming significant engineering challenges).