Yes, this is very sad news. But thanks to this thread and amazing people who write here, I think we will always have a chance, that Python 3.7 will be functional under XP.
JFYI, FontForge has a newer version, based on Python 3.7.4. All the problems that I have mentioned above are also relevant to it. For my experiments I choose not the latest version, based on Python 2.7.16 , because it is little easier to adapt under XP.