Hummm... I never had problem with steering breaking.
If you tell us in which kind of situation this is actually breaking... then we might be able to figure out the most probable cause.
It could be binding somewhere and the servo is stronger than the original and at some point, it just break.
Or it could be that you're hitting stuff way harder (more speed, more force on impact) and it pushed the steering assembly into something it's not suppose to hit (within the car) and breaks it off.

But regardless of how it happens... I'm thinking it might be easy enough to fix - you need something stronger there.
You could buy a small aluminum rod and bash it into the shape of a small plate, then drill holes based on the current piece that's always breaking. Then tap the holes so the screw for the turnbuckle catch or just use a nut (I think there's enough place in there to add a 3mm nut).