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.)

I can guarantee you one thing - github's problem isn't coming from git.

Considering all the ci/cd pipelines, PR & issue discussions, social media tracking, rich data and else that github hosts if their true issue is the actual meat and potatoes of running git I would be gobsmacked.

What are you referring to when you say it's "fundamentally computationally inefficient"? It's pretty efficient because it's content-addressed, plus optimizations to reduce storage and data transfer with packfiles.