Most mathematicians aren't interested in refactoring their mathematical "codebase", nor experimenting with axioms. They simply want to understand and discover more math. The reasons you state for your interest in formalisation don't appeal to most mathematicians.
Concerning analogies and borrowing techniques between fields, this is absolutely something humans are good at and which it is very hard for computers to do. Why do you think otherwise? To take a very simple example, most mathematical objects can be represented in different ways. A mathematician can fluently move between these representations, whereas computers cannot. This is a largely the obstacle for the adoption of proof assistants among mathematicians.
Concerning analogies and borrowing techniques between fields, this is absolutely something humans are good at and which it is very hard for computers to do. Why do you think otherwise? To take a very simple example, most mathematical objects can be represented in different ways. A mathematician can fluently move between these representations, whereas computers cannot. This is a largely the obstacle for the adoption of proof assistants among mathematicians.