Actually, SW is just the AutoCAD of 3D. They did a phenomenal job marketing and grabbed a huge market share early on. SE is not dead, nor is IV or Alibre or WildFire, or any other. They are all still mainstream. They just don't have the market share of SW nor do they have their name plastered in as many places as SW does. I can't believe how many abstract trade journals I see SW ads. Some of them don't even apply to MCAD software, yet SW is there.
And by the way, I have many clients that use SE and Alibre. I have only 1 right now that uses SW. And I have another client who was doing a "hunt" for the right MCAD package and SW was last on his list. Short of sounding like JB, VX was actually number 1 - which if you filter JB out of your newsreader and actually test the package, it isn't all that bad. I was pleasantly surprised.