They wrote a blog post on how clever they think all their workarounds are, at least one of which involves sparse-checkout -- which is perilously close to chopping up your monorepo into several, while still pretending monorepo is fine.
I feel like somebody's job and/or ego is heavily invested in keeping things as they are, even if it demonstrably does not scale to their needs, and the solution is blindingly obvious to even a casual observer.
That is institutional insanity.