F5 manages the delivery of applications across multiple networks, which is a complex problem, especially when some of those networks lie outside of a business' direct control. That's why F5 takes a holistic approach to application delivery networking.
Businesses try to address this complexity in many different ways: buying more bandwidth, installing additional servers, even rewriting applications. Unfortunately, these strategies are usually costly, and they are only partial fixes.
Deploying F5 products at key points in the network is generally far less expensive -- and their products address the underlying problems more directly and more effectively.