I think infinity in the gp comment could well be defined as, "the new AGI regime will or won't obliterate me." The gp comment is just Pascal's Wager, with AGI taking the part of God, and "infinite returns" taking the part of an eternity in Heaven or Hell.
- If OpenAI does not achieve AGI, and you invested in it, you lose some finite money (or not, depending on the value of their other R&D)
- If OpenAI does not achieve AGI, and you did not invest in it, you saved some finite money, which you could invest elsewhere for finite returns
- If OpenAI achieves AGI and you invested in it, you get infinite returns, because AGI will capture all economic value
- If OpenAI achieves AGI and you did not invest in it, you get negative infinite returns, because all other economic value is obliterated by AGI
Therefore, one must invest (or in this case, "work on the most important problem of our time").
(And yes, this tongue-in-cheek.)