It's an interesting social problem in how you manage those project / library / repository boundaries. On the flipside, though, it's been well documented that among many of the major monorepos those boundaries still exist, they just become far more opaque because no one has to track them. You find the weird gatekeepers in the dark that spring out only when you get late in your code review process because you touched "their" file and they got an automated notice from a hidden rules engine in your CI process you didn't even realize existed.

In the polyrepo case those boundaries have to be made explicit (otherwise no one gets anything done) and those owners should be easily visible. You may not like the friction they sometimes bring to the table, but at least it won't be a surprise.