I think the market has the potential to be 1 or 2 trillion in the US, 10% to 20% of labor costs. I say this because I believe most companies would not blink at spending that money to supply their workforce with AI tools assuming the AI actually did the work.

The winner take all network effects are probably not there in this case, but still if Anthropic is a large player and has 20-30% of the market they could have a revenue in the hundreds of billions.

Double the size of the market to include most of the rest of the world and the 500B is suddenly under 20% market share.

and if 20% of labor costs are translated (a.k.a 20% more unemployment), who's buying all the goods and services those companies create?

The tech companies will just parrot "UBI" at that point, but given how adverse they are to being taxed, how UBI would be financed, is an unanswered question.