I'm thinking if you could press out the ball joint and sleeve it with a threaded insert you could have a replaceable the ball joint,
I'm unsure how directly threading casted aluminum would hold up.
You'd have to hope a threaded insert would fit the hole left behind, drill out the hole to fit an insert OR we could have a sleeve fabricated to match the hole left behind.
then you'd have to find a ball joint that matches up with threaded sleeve and the hub.
I'm not and engineer or fabricator, but it seems possible.
I know some will wonder why bother when there are other options. Well, this would be cheaper and I'm wondering if anyone has explored this idea.
after a brief search around I found these, im sure there are others out there.
Accessories | QA1
Steel Upper Ball Joint Sleeve, K772 Style