@aradi yes, excellent feedback and I agree. Being able to offer the old F77 interfaces (e.g., as global routines that internally use and call the modern routine version) would be good, that way the new library can be used as a drop-in replacement in existing codes, and they can later gradually migrate to the new interface if needed.
In general the modern version does not offer faster code. Just a maintained library.
And yes, you are right, there are no guarantees of maintenance, however the new code is on github now under fortran-lang, and anybody can contribute to it and help maintain it. For legacy codes that is often not true. Although both lapack and arpack-ng are already on github and one can contribute to them.