The simple answer is consistency and engaging with their audience to build a community-like brand. To become "massive" you've got to add value and constantly be creating and curating content that your audience can identify with. It's a full time job. You're onto a good start with your research. Focus on the type of content they are putting out and how often they are doing so. I hope this answers your question. All the best with your project!

In recent times a lot of companies have been seeing that 80%+ of their leads come from social media marketing. All of these companies have a polished social media strategy. You would not generate leads if you just have a page and post content that you think relates to your offering. So to answer your question, it all depends on your social media efforts/strategy.