Because it takes time. It wasn’t until the 1970s that Babbage’s contributions were fully understood (see Bruce Collier’s thesis), and until the 1980s that his plans had been deciphered by the likes of Allan Bromley. Only then could the Difference Engine No. 2 be constructed. It was finished in 1991. In many ways, The Difference Engine No. 2 was an ‘easy’ project because Babbage had left complete plans for it. The Analytical Engine is a different matter.
Babbage left multiple plans for the Analytical Engine and was constantly refining its design up until his death. To build the Analytical Engine first requires a research project to figure out which plan to build from.
I love the idea of Babbage’s Analytical Engine finally being built. Sure, my computer is fast and powerful, but you can’t see the data running through the chips. A dream of mine is to create a mechanical computer that uses balls rolling along tracks to play Tic-Tac-Toe.
^^ exactly. You can’t see the data running through the chips. I’ve been working hard on a microprocessor in VHDL for class and it’s amazing what goes on inside those guys. I read about Babbage a while back, this is a fascinating post.
Also ^^, that Tic-Tac-Toe machine would be awesome.