[jandrewrogers]

My recollection is that it came down to two factors. Pragmatically, the pool of highly skilled C++ programmers was vastly larger and the ecosystem was much more vibrant, so development scaled more easily and had a lower maintenance risk. By 2005 they had empirical evidence that it was possible, albeit more difficult, to build high-reliability software in C++ as the language and tooling matured.

These days they are even more comfortable using C++ than they were back then due to improvements in process, tooling, and language.