> At least one package in 3.8 still contained a dependency on the C++ 
> runtime

FWIW, the very first thing that I checked was the dependencies of pythonw.exe, in case maybe I had a dependent DLL that's not distributed with Windows. There's nothing out of the ordinary:

    C:\Program Files\Python37>sigcheck -nobanner pythonw.exe
    C:\Program Files\Python37\pythonw.exe:
            Verified:       Signed
            Signing date:   7:12 PM 10/14/2019
            Publisher:      Python Software Foundation
            Company:        Python Software Foundation
            Description:    Python
            Product:        Python
            Prod version:   3.7.5
            File version:   3.7.5
            MachineType:    64-bit

    C:\Program Files\Python37>dumpbin /nologo /dependents pythonw.exe

    Dump of file pythonw.exe

    File Type: EXECUTABLE IMAGE

      Image has the following dependencies:

        python37.dll
        VCRUNTIME140.dll
        api-ms-win-crt-runtime-l1-1-0.dll
        api-ms-win-crt-math-l1-1-0.dll
        api-ms-win-crt-stdio-l1-1-0.dll
        api-ms-win-crt-locale-l1-1-0.dll
        api-ms-win-crt-heap-l1-1-0.dll
        KERNEL32.dll

      Summary

            1000 .data
            1000 .pdata
            1000 .rdata
            1000 .reloc
           14000 .rsrc
            2000 .text