Projects like KDE, the GIMP, GNOME, Lucene, Jython, LLVM, Asterisk, Audacity, CMake, and Danger that got started in C, C++, or Java in the 01997–02002 period are still based on those languages today. OCaml would have been a reasonable language for all of these, though a new interpreter for Python in OCaml would have lacked Jython's key feature, the ability to easily script other things written in Java.
(Danger? Well, Danger as such ended in 02011, but Andy Rubin founded Danger in 01999 and left to found Android in 02003, which ended up making a Java-based smartphone much like Danger's Java-based smartphone, but less locked down.)
The fact that Java focused heavily on performance starting in 01997, when Sun bought Animorphic, meant that a lot of things were able to be written in Java in the 02000s, things that were previously just unthinkable. Lucene predates HotSpot by a bit, but the whole Hadoop ecosystem that grew out of it only makes sense in a HotSpot world. Minecraft obviously pushes performance heavily. SPARK is written in Scala, but OCaml would have been a good fit too—if Hadoop had gone that direction.