While you may wonder/think that Google uses git and various fashionable methods interacting with a distributed version control system, they do not!
Here is a great explanation of what Google does regarding source control and more importantly: why they do it this way
Continuing on this train of thought: What would you use when you want to centralize all the code into 1 repo? Google ditched Perforce over something they developed themselves. While fun and challenging: not an option for us mere mortals.
Perhaps Microsoft comes to the rescue? The ‘New Microsoft’ says they are very pro-open-source and they tried to solve some of the problems with massive git repos by developing GVFS
Soure: https://gvfs.io/ and https://blogs.msdn.microsoft.com/bharry/2017/02/07/more-on-gvfs/
With this implemented essentially you are centralizing the massive repo and only have a ‘sparse repo’ or view on the central repo.
If used right: perhaps this will be beneficial for making a step to Trunk Based Development.
Let’s give this a try!