You can't discourage people from experimenting with new languages, frameworks, design patterns, etcetera, just because some people might use it and fail.
We actually learn a lot more from failures than successes.
The problem that I see is that developers only want to work on what is new. They don't want to work with C++ because it's old. They don't want to work with Java because it's old. They don't want to work with Ruby because even it is old. It's the same thing with frameworks. There has been an explosion of frameworks because developers can't be caught dead working on something older than 6 months.
If one's intention is to rewrite entire applications every year, knock yourself out. But if you're writing apps for customers who expect it to be solid and remain in the field for a useful amount of time, then you need the reliability of C++ or Java or C. Not some language someone whipped together in a handful of weekends.
Another commenter mentioned beginning development because it was fun. I did too. It still is, but I also grew to care about the products I develop. And no, it's not fun to chase issues with immature technology when a customer is wanting answers.
Something we can quantitatively take away from the slur of new languages is that new languages are easier now than ever to create/implement. This should be a good thing. This means faster iteration can occur. Even if that iteration is not necessarily taking place, the creation of new languages verifies this ability.