Hi, JSM is actually being used by many on online sites, and it's been for a lot more than a year.
It's been a one man show regarding development, but he's giving actual love to the extension day after day, and slowly squashing bugs one after another.
It has still some bug, but is definitely usable, and some other dev is also contributing, so there's hope to see it bug free.
Maybe you used the wrong word describing his tireless work, you can help improve it contributing as well, on github http://jmp.sh/QznJ5kk
and on JSM forum, work is now focused on making it work for Joomla 4.
I'm also heppy someone is trying to revive joomleague, it's good to have choice!!