I think you're basically right, but the waters are murkier than you give them credit for. I don't really buy any definition of "successful mainstream languages" that doesn't include Ruby and PHP, and neither of those started with any sort of corporate backing, and still aren't tightly associated with any single "big company".
I think Ruby is too small to be considered an industry-wide success. PHP is indeed extremely successful, and should be added to my small list of scripting languages (in fact, it has been far more successful than Python): BASIC, PHP, Python. However, those exceptions are still only for scripting languages (even if you count Ruby), and none of the languages mentioned by the comment I responded to -- except Groovy -- falls in that category.
I think Ruby is too small to be considered an industry-wide success.
I'm not necessarily the biggest fan of the TIOBE index, but in this case I'll cite it, as it is "close enough" I think. Ruby is #13 right now, which isn't bad. And while I think TIOBE has some warts, I think it's safe to say that anything in the top 20 is fairly successful, and anything in the top 50 is "successful" to a certain degree.
This thread is a bit old for me to expect a response, but I'm always curious when I see people using this terminology: what purpose does the term "scripting language" serve? It doesn't seem to tell me anything about what a language is useful for, its runtime characteristics, or the style or philosophy it encourages.
