I think you are correct in that success results in the automation of labour and increasing the capital share of economic output to functionally 100%.
I do not think it follows that this grants investors in these AI labs part of the lightcone. If they are locked in perfect competition, there is no surplus to return to investors. Investors in natural resources, land, or perhaps data collection companies could expect everything they own to become vastly more valuable. But the investors in AI labs see their investment locked in a situation where profit margins are zero, and fail to claim the portion of the lightcone that capital might have otherwise offered them.
I think you are correct in that success results in the automation of labour and increasing the capital share of economic output to functionally 100%.
I do not think it follows that this grants investors in these AI labs part of the lightcone. If they are locked in perfect competition, there is no surplus to return to investors. Investors in natural resources, land, or perhaps data collection companies could expect everything they own to become vastly more valuable. But the investors in AI labs see their investment locked in a situation where profit margins are zero, and fail to claim the portion of the lightcone that capital might have otherwise offered them.