I agree absolutely!
I was disappointed to note that Leonardo da Vinci wasn't considered either. A number of other people whose creativity and thought contributed were mentioned, e.g. Darwin, Einstein, to name a couple, but each of these three, as well as other philosophers named, had a specific influence in a specific arena. Making it possible for the written word to be accessible to the greater populace has to have been the most profound comprehensive influence.
In my own work I just can't imagine having to start from scratch; we'd never, ever know what we do now. All creative thought is based on something that is observed firsthand or learned in another way. The right conditions have to be in place for just the right individuals to perceive the right relationships, to produce the "aha!". That "aha" provides the first rung on the new ladder. Without dissemination of that information and those ideas, the pool of individuals who might have access to those elements would be extremely limited, and progress of any sort would be extremely hampered.
Well I had three main criteria for selecting my top 5. First, they have to be known so that excludes the inventor of writing, the plow, language, fire, etc.
Second, I judged their quantitative influence, that is how many people did they influence.
Thirdly, I judged their qualitative influence, that is, how did their influence impact change.
Balancing those three criteria it became very obvious that Muhammad was the most influential person who ever lived due to both his influence in religion and politics. To use an analogy his influence was like combining the influence of both Jesus and Augustus Ceaser. So Muhammad walks away with #1.
Newton was a fairly easy decision too. From the time of Jesus to the 17th century (1700 years) there was little change in how people had lived. 300 years later, thanks to Newton, our world has been profoundly changed by modern science and technology. If this was a list of the greatest geniuses of all time, Newton would be number one on that list.
Jesus makes number 3 as the most influential philosopher in human history.
Guttenburg and Tsai Lun complete the list because their inventions were so profound that they became the vehicles in which modern civilization was built. Only the invention of the plow and writing rank up with their inventions, unfortunately, those inventors are lost to history.