I am no SaaS-strategy expert but I work for a SaaS ISV and have been a student and propenent of the Internet as a transformative tool since before the inception of the World Wide Web.
It seems to me that a lot of the sea change in attitudes in the general population towards SaaS and SaaS-like offerings comes from much simpler origins. In the last 6 years since the .com boom and bust there has been gradual but overwhelming upsurge in the use of Web-based services that go beyond simple information gathering and e-commerce. From online banking and tax preperation to personal services like Evite, iTunes, flickr to online social networking/gaming people are getting comfortable using the the internet in deeper ways than as a simple research/buy tool.
I believe that this has created a gradual change in perception that has impacted many more people at a deeper level than all the talk of "The Network is the Computer" by technophiles. This creeping but inexorable blurring of the boundaries between my computer (or phone or Nintendo DS) and the Internet is what makes SaaS make sense to millions of people who don't know what SaaS is.
People are experiencing the value of "doing things on the web" at a very personal level and I believe this will cause them to accept SaaS solutions without a second thought. We are approaching a time where many people won't question running SaaS solutions because they are inherently comfortable using the web to get things done.
Mark Heaney
SMBLive