Other ways to disrupt established business are to visit their parking lot and slash everyone's tires, cut power and internet to their company buildings, slander them on public television, drive by their building and honk a really loud horn, find their business partners and spread false rumors, DDoS their website, make false tips to the SEC that they're scamming investors, etc.
That's the image that appears in my head whenever I hear about some startup disrupting an industry; like they're a criminal with poor impulse control.