There's a full discussion of the phrase here

Your interpretation, to be left with an empty bag that previously had something valuable, is one of several interpretations, but not the earliest.

The original seems to be, the member of the group holding a bag of contraband when the authorities intervene.

I think this second meaning is the more compelling: the group sought a benefit but only one bears the cost. Or, each member of the group took the risk but that risk only materialised for one member.

I mean, after you share out a bag of gold, including giving yourself a share, the bag will be empty.

No, I know what it means. I don't think it applies here. It would apply to something like a pump and dump scheme, where the people know the bag is already empty, but they fluff it up and try to pass it off on someone else before the whole thing collapses.

That's not what these companies are doing. They legitimately believe that AI will eventually become profitable and are trying to corner the market and be the dominant player. They WANT the crash. They just want to be the ones that survive it. That's not the same as trying to leave someone else with the bag at the end of it.

I thought "get that bag" was specifically to encourage women chasing money to buy synecdochic luxury purses.