Earlier quoted context omitted.
I agree with this, but I'd add that we developers tend to make an RDBMS do everything because it's what they're familiar with. NoSQL is an alternative to solve a specific problem, but you can't see that problem if you're ignorant of it. It's like my experience with SVN vs Git. I didn't know how useful and more efficient my workflow would be if I used branches, so I never saw why Git was useful. Sure I could branch in…
"SVN vs Git" An excellent comparative case in point that in my opinion actually undercuts what you are asserting. You do not lose features and functionality in that transition (where as noSQL is by design reductive), and further, Git is a replacement for SVN and not a complementary tool.
The lesson Git, Ruby, Subversion, Apache, and many other projects have taught me is that instead of saying "What I have is fine, I don't need what you have", I need to ask "Why do you use what you use, why does it help you, and how might it help me?