Git itself is kind of a fundamentally computationally inefficient way to store and retrieve information. If the problem to solve were simply "store and version this text", 14 billion commits in a year would not even be considered a lot.

In other words, a centralized version control system built from the ground up to operate at scale would do far more for scalability than anything GitHub could possibly do to optimize their Git operations. Every major tech company (Amazon, Meta, Google, etc) is already doing something like this internally.

Though this would require people to start using a github-specific client rather than the traditional git+ssh. (Though the github client could still maintain a git repo locally, for compat.)