The killer feature of any SaaS business is the massive reduction of operational cost and complexity including setup, configuration, ongoing maintenance and upgrades. Given the runaway success of SaaS in recent decades, we can clearly see that using a SaaS model instead of traditional shrink-wrapped software has made perfect financial sense for many customers.
This in line with a theory that says that is a constant level of complexity in a system at any given time—IT organizations can deal with this by investing in-house (investing in a team that handles complexity), or outsourcing to a partner or SaaS/PaaS/IaaS vendor (exchanging money for complexity). When one combines the latter with an OpEx vs. CapEx financial model, easy installation/setup, and flexible pay-as-you-grow options—it becomes be very difficult to justify any other delivery model for generic software.
