You can also use the free (and much simpler) Google Sketchup. My opinions about blender are not suitable language for the forum...
You make one critical error in logic however. I'll illustrate it thus:
When Sculpts came out, did every single thing that was made for SL have to be changed to take advantage of it? Did you, in fact, have to learn sculpts and change every single item you sold to incorporate them? Unless you are making furry avatars, then the probable answer is no. Some things were superior with them and some things were not. (None of my stuff for sale uses sculpts, for instance. And the stuff still sells.) Look at Xstreet (sorry: Marketplace) and tell me what percentage of the stuff there is sculpted. It is far less than 100% and is actually even less than 10% of the items sold overall.
Now. We've seen that sculpts did not mean instant doom to everyone making non-sculpt items. There are many, many non-sculpt items for sale even today. So what makes you think that Meshes will be any different? What is it about a mesh that will make me want to use one to create a sphere rather than just rezzing a sphere?
Jsut a quick comment on the sculpt comparison. I think the major flaw in the comparison is that when sculpts came into play, there were no Major "sculpters" in existance. It was a fair process in which everyone had to learn from the same starting point. I think what everyone sees here is that there are people already, not even inworld yet that have years if not a decade under their belt that can just come in and take over whereas sculpts even the professional level creators had no clue how to use the tools to sculpt. They did not mean instant doom because noone knew jack about them. I see both sides on this, Sl does need to evolve, Mesh for SL is good for SL and the people who wander around and look at pretty things, but I do in fact think its going to bury and alienate many many of us misfits that found a home here, and to learn this technology now, could almost be too late.