I'm quite sure the big apps aren't going anywhere for a relatively long time.  Autodesk is a very wealthy company, judging from the profits it's earned annually before acquiring Alias for over $100 million.  Most of the applications under it's umbrella will probably endure.

I think 3dsmax, if anything, might be the one application at risk here in the long run.  Now that it's parent company also owns Maya (which is arguably a better app), Autodesk may eventually dissolve 3dsmax and integrate some of it's key features into the Maya architecture (it's PFlow system and subD modelling tools come to mind), or combine the best features of both apps into an entirely new core.  Autodesk already has 3dsVIZ, which is geared toward the arch/VIZ industry, so they could continue to dev that application, and getting rid of Max wouldn't hurt them much financially.  Then again, there's SO many 3rd party companies out there that depend on the 3dsmax plugin architecture for their entire business, I wonder if Autodesk would have the balls to kill that.

I'm a 3dsmax user myself, so I'm hoping my speculations are TOTALLY off, but it just seems like eventually, somewhere down the road, this could happen.

As for low-end or mid-range 3d applications like Poser, etc.  They should continue to thrive, unless/until the open-source scene forces the high-end industry to cut prices more and more, and eventually "choke out" the smaller software vendors.  :unsure:

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Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.