That’d be awesome, and we could take three days to traverse a reasonable sized city transporting, well, nothing because they invented the internal combustion engine for a very good reason
I've read historians who think the size of ancient cities was limited to about 1 million people for so long simply because that was about as large as a city could be before traversing it took over a day. As soon as rail roads were invented cities could grow much larger.
As for cycling, I think it's best not to confuse commuter cycling with road cyclists. Sure, here in Australia most commuter cyclists are Lycra clad, but that's more because commuter cycling requires an unnecessary amount of shared road spaces. In places where cycle paths are separated from the road, more people cycle and there is less congestion and accidents.
Studies have shown that commuters tend to take the method which is fastest, regardless of what that method is. Commuter cycling also has massive economic benefits (less road wear, less health care system burden and less tax dollars spent on buses/ trains).
Australian cities are poorly designed for people. Not as bad as American cities, but we have designed our cities around cars, rather than around people. That's why everyone has huge blocks of land, suburbs require cars to navigate and commercial centres need massive car parks. Many European cities are far more practical for actually living in because they were built in a time where people had to walk to get anywhere.
There's a lot to love about Australia, but our transportation infrastructure is not one of those things.