SaaS solved the issue of: I want continually improved and supported software, but I don't want to pay $5000 (or whatever fee makes sense) upfront for it.
I used to work for a CD / DVD / Blu ray mastering company that powered pretty much every major movie release (mastering), and every consumer CD burner (drivers).
Meanwhile, people call in complaining that X is broken, on a version we released 6 years ago and no longer maintain. Since we had to float 2 years of revenue per customer, a license was around $3000, meaning smaller shops hated upgrading...
To claim that now that they're familiar with our software, all their processes use it, that they're "addicted" is quite the leap.