As a way of explanation as to why I have embarked on this route to imagine a history rewritten, I submit to you a key element to which the steampunk past made possible could have hinged.
A steam-powered device used for computation was imagined in 1837 by the amazing Charles Babbage, who called the contraption an "analytical engine". It remains one of the greatest inventions that ever was conceived but never came to fruition, due to a variety of reasons, including Babbage being turned down for governmental funding that would have made his dream a reality.
Babbage died before he could see out the construction of the analytical engine himself, with only partial pieces finished (on display in the London Science Museum), and a demonstration version of what he termed a "mill" completed by his son Henry P. Babbage. The "mill" was essentially a CPU, an arithmetical unit able to perform all four arithmetic operations, plus comparisons and square roots. If built, the analytical engine would have been about the size of a small steam locomotive, and capable of holding approximately 20.7 kilobytes of memory, with 1.7 kilobytes of expandable memory.
Before frowning at the juxtaposition of the massive size of the entire device to the seemingly small size of the memory capacity, keep in mind that it would have been in many ways more advanced than some of the first computers that emerged a century later in the 1940s, as it would have been digital, programmable, and a "universal Turing machine" long before Alan Turing introduced his own concept in 1936.
All of this begs the question of how much of a setback this put the advance of technology, and if even greater advances and scientific breakthroughs could have been possible by now. And, if so, would the results be beneficial or detrimental to our society as a whole?
Interestingly enough, science blogger John Graham-Cumming has started a campaign to finally build the marvelous device while using Babbage's original blueprints stored at the Science Museum in London. If built, it would the first complete working model of the machine. It would also be a humanitarian endeavor, as Mr. Graham-Cumming has stated his intent to donate the completed machine to either London's Science Museum or the National Museum of Computing. His Plan98.org website is asking 50,000 people to pledge money towards building the machine. So far, 3,448 have already pledged their support; however, 46,552 will be needed by the deadline on January 31, 2011 to make an important piece of potential steampunk history a present-day reality.