What you have with integrating competing solutions in IT is a lot of work to make it work. If you think of a user organization like a bank or retailer, or aircraft manufacture, there are certain barriers that this causes them. The time barrier, for any organization, the time to market new products and services is a big issue. They all want to provide, all user organizations, their IT departments, all want to provide better products, services, and tools to their end users. Either to make them more productive, or to make them more competitive.
Time is a big issue.
There is time in instillation, there is time in training, and if you are dealing with multiple different operating systems, interoperability with a human is an issue that you have to address as well. Obviously integration, if you are going to have to make two things work together that were not designed to work together, you have an implementation problem. If you have two different technologies that need to be supported, you need two different skills in the work force to support them for the rest of their natural life. There is a risk that you may not be able to provide service as you would want to. Obviously although many of the products individually have superb security devices, when you have to join them together, what you find in the joins is this is the gap where people can get in.