Generally the network effects (demand side scale effects) cause one standard take over and drive out a competing standard. Sometimes multiple standards survive over time because they operate in seperate niches. Which side of the road people drive on is an example of that. Here are some actual numbers; which surprised me.
Almost exactly one third drive on the left while two thirds drive on the right. What’s the chance of that? I wonder if it means something.

In a modern example, it’s hard to see how .NET and J2EE can both survive in the long run. I can’t see how they have different niches.

Getting a winner requires that one bandwagon get out in front of the other. How far in front? Well when the one bandwagon begins to capture enough advantage – enough extra value – usual from it’s network effects to pull people off the other bandwagon – to pay their switching costs.

Easy way to get that network effect advantage is to capture a lot of users fast. Users who are just entering the game for the first time. So they don’t have as high switching costs. New users are, sadly, often quite nieve. They want to pick the right bandwagon. They don’t have much information. They holdback. They look for signs of what the future might hold. They attempt to see thru the fog of standards war advertising. They do what the guy next door did. They build out from what they aready have. They casually pick something, not realising they are picking a bandwagon.