The arguments given all seem reasonably convincing. The interesting thing is the kind of argument this blog and some here engage in. That is, one looks at argu

The arguments given all seem reasonably convincing. The interesting thing is the kind of argument this blog and some here engage in. That is, one looks at argument X, decides it's not convincing and then pushes argument Y. It's sort of a single-cause fallacy. Maybe bad roads weren't enough but they contributed. Maybe technological limitations weren't enough but they contributed, etc. The problem is that combining factors are hard to see and hard to argue for. A factor here (a meta-factor, haha), modeling how all the different factors came together or didn't come together is hard. You'd need a historical look at how the bicycle was invented and a look at how at how could have been invented earlier but wasn't. This goes into how people think, how people design machines, how people allocate resources, etc. Which is to say we'll likely never know how the associated factor contributed and how much. But we can tell that the vagueness of the situation doesn't stop people arguing.