Many grill stars are hardly repairable, and that's part of the issue.
There are actually three pieces to the assembly which I believe was only sold as a complete assembly; someone correct me if I'm wrong. I had a new one in the OEM box.
There is the barrel, and the star which is two pieces. Cast of pot metal which has very little strength in any metric, it usually breaks where the star attaches to the ring. You cannot weld pot metal. You can try some kind of goop such as JB Weld, various epoxy or other resins, but you won't end up with anything nearly as strong as the original which wasn't strong to begin with.
Some years ago, a creative enthusiast (don't ask, I don't know him, it's just a story told to me by others) cast the star assembly in brass/bronze and made it available. That was great until the Daimler attorneys got wind of it.
Andrew you'll appreciate this story. When my car was being restored, it didn't have any grill star or barrel. So my restorer found a used one for maybe $50. It was good, but not great: the chrome was flaking off in a couple of places. A few years later a friend offerered me a NOS OEM unit in the original box for like $300. At that time the new ones were maybe $400 or $500 from the classic center. So, I jumped at that, and swapped it out. I eventually sold my used one for about what I paid for the new one...
Meanwhile, at that time on the forums, people were SCREAMING at the totally outrageous price of $500 for a new grill star/barrel assembly. While they were kicking and screaming and not buying what they needed, the price kept going up. And up. And up. And yes, as you point out the new ones when last sold by the Classic Center were in the thousands...there's probably a few who are kicking and screaming that they should have bought one at $500...