There are many success stories when it comes to software development staff augmentation.
Before becoming popular, brands like WhatsApp, Slack, and Skype began as startups. They were able to expand quickly via offshore staff augmentation.
Even big companies choose staff augmentation for strategic reasons. For instance, Time Warner Cable (TWC) needed help for a networking tech project. So they hired specialized skills via a staffing partner. They were able to complete the project ahead of schedule.