Why Is Cybersecurity Still a Problem in SCADA and Control Networks?

IT engineers have been dealing successfully with cybersecurity issues for years, and there are many security products in daily use in enterprise networks. Why is cybersecurity such a challenge on control networks? Why can't the same tools and techniques be used to secure these systems? The answer to these questions lie in understanding the unique requirements of control and SCADA networks, and applying cybersecurity strategies in ways that are appropriate to these applications.