I don't quite understand what you're saying. Using proprietary or open source software isn't a determining factor in whether the industry using it will grow quickly or slowly. For example, most computer animation software (Maya, SoftImage, ...) is closed source, but CGI in films and TV has experienced huge growth in the last 20 years.

In any case, even though ESRI is the market leader, there's quite a bit of open source GIS software (GRSS, QGis, PostGis, etc.). Entrenched markets like that don't get "disrupted" by magic, it requires people to jump in and use the alternatives on real projects.