building with 64-bit BLAS is blocked by other 64-bit external packages

PETSc has some capacity to build against 64-bit BLAS, with configuration option --with-64-bit-blas-indices is provided separately from --with-64-bit-indices.

But most supported external packages are treated incompatible, with Package.requires32bitintblas defaulting to 1 (incompatible) in config/BuildSystem/config/package.py

Does PETSc really need to be that inflexible about 64-bit BLAS support?

For instance, in the debian packages, there are 64-bit builds of scalapack, Hypre and MUMPS (true, debian does not have 64-bit build of superlu and superlu-dist)

Should PETSc make it possible to allow 64-bit BLAS builds with scalapack, Hypre and MUMPS, or are there other complications that need to be thought of?