Sometimes people may consider switching to another software depending on their need and/or budget. Couple of forum members recently mentioned that they come from another CAD software and chose to learn Rhino instead.
I can imagine that people who have been using Alias or ICEM for decades will not be willing to switch to Rhino, because they already have experience with much more powerful modeling tools and feel comfortable using them. However, if Rhino has better NURBS modeling tools that would attract many newcomers (students, freelancers, small companies etc) who are just about to decide which modeling program to pick and use as their main CAD software.
Here is another example why Rhino really needs some improvements of its existing tools: