I have a lifetime membership of D5, and use several of the extended themes.
It is a pain to manually update each site when a new version appears i.e. I cannot update D5 themes directly from WP Dashboard. I have to upload new versions of themes via a manual process. I’m sure D5 has it’s own reasons for this.
However, I can’t see it being beyond the ‘wit of man’ to create a facility where for licenced users dashboard updates can be done instead of manual updates. To be clear, I require no advice on work-arounds or on easing the manual update process.
I think it is in D5’s interest to find a secure cost-effective way for users like myself to be better served.