That's a fair point, although I can think of examples in the IDE reals as well - e.g. in the world of Java Eclipse and NetBeans were popular (and open-source), but gradually IntelliJ IDEA dominated them for various reasons. I also remember all the Borland tools (super popular in the 90s) that have mostly disappeared by now. I definitely think that open-source projects are more likely to survive long-term, but it's not like they don't fail.

Btw, I think TextMate is open-source these days as well.