To me it seems that every task done by humans will be supported or even replaced by AI. I already see it happening, just 2 years into the new LLM area: Programming, designing, writing, research, driving. How could that not result in a doubling in software use?

I did not assume that one player is going to capture all value. I stated the number for 10% and 90% market share. Today, AWS has 30% market share of cloud computing and Google has 90% market share of search. Assuming the market leader in AI will achieve between 10 and 90 percent market share seems reasonable to me.