> Briefly, the argument goes that if there is a 0.001% chance of AGI delivering an extremely large amount of value, and 99.999% chance of much less or zero value, then the EV is still extremely large because (0.001% * very_large_value) + (99.999% * small_value) = very_large_value

I haven't heard of that being the argument. The main perspective I'm aware of is that more powerful AI models have a compounding multiplier on productivity, and this trend seems likely to continue at least in the near future considering how much better coding models are at boosting productivity now compared to last year.