These types of systems are interesting, but I wonder if there's any use case where you would prefer them over the one you're browsing from.
FriendOS is arguably also the most advanced and complete of these systems: https://friendos.com/
FriendOS is arguably also the most advanced and complete of these systems: https://friendos.com/
This is a great illustration of this type of business: https://apenwarr.ca/log/20120326. A lot of customers totally need, not just want, this type of thing.
Puter/FriendOS type systems can graft upon some modern features on top of all legacy apps, which is far far better than having to build it out for every single one. Especially as the market lies more in the long tail of the custom software tailed to specific companies, that has been chugging along for 15 years in maintenance mode.