Why Wallonia in particular? What made it so suited for industrial development? It has always struck me as kind of odd, because before the Industrial Revolution came along Wallonia was (to my best knowledge) not particularly wealthy or economically successful compared to other regions in the proximity (Holland, Brabant, the Rhine cities or the Ile-de-France).
I have not heard of Wallonie being called "the first region o nthe European continent to industrialize so thoroughly," can you share your source, please?
Regardless, a lot of the industrial machines were invented to help with coal mining. Up to the 16th century, the most developed coal mining regions were around Liège/Carleroi/Mons, and around Aachen/Ruhr. In the early modern era, an ironworks/foundry industry were built around these areas, producing many weapons for the Eighty Years War and the Thirty Years War.
Historically, Holland and Brabant were wealthy due to other reasons, namely fishing and trade for Holland (if we are to talk about early modern to modern), and textiles and trade for Brabant (at least up to the early modern era). Brabant in particular suffered tremendously due to the sack of Antwerp and the blockade of the Scheldt. The cities of Noord and Zuid Holland rose as Antwerp's prowess declined.
Source: The Cambridge Economic History of Europe edited by E.E.Rich, C.H.Wilson.