Isn't Google like this, too? They have their own source control system, their own IDE, their own databases.
It seems like any giant organization eventually develops its own software center of gravity.
It seems like any giant organization eventually develops its own software center of gravity.
The only real difference there (although it is a significant one) is that most of those internal Google tools tended to be very good, often ahead of the external state-of-the-art. That's a very different feeling to a baroque old stack inside a bank somewhere. Maybe the external world has caught up on a bunch of them more recently though which would start to change that.