I think perls do have a built in support for both architecture-dependant and version-dependant directories (and both) in @INC. At least, I can see that support in lib. If I run the (private) sub lib::_get_dirs using
I see:perl -le "require lib; print for lib::_get_dirs()"
These are subdirectories for each directory you add with use lib, that also get added to @INC./MSWin32-x64-multi-thread/auto /MSWin32-x64-multi-thread /5.24.0 /5.24.0/MSWin32-x64-multi-thread
So... version dependent library roots are defenitely possible in a common library directory tree.