Does it matter if they can't ever stop training though? Like, this argument usually seems to imply that training is a one-off, not an ongoing process. I could save a lot of money if I stopped eating, but it'd be a short lived experiment.

I'll be convinced they're actually making money when they stop asking for $30 billion funding rounds. None of that money is free! Whoever is giving them that money wants a return on their investment, somehow.

At some point the players will need to reach profitability. Even if they're subsidising it with other revenue - they'll only be willing to do that as long as it drives rising inference revenue.

Once that happens, whomever is left standing can dial back the training investment to whatever their share of inference can bear.

It matters because as long as they are selling inference for less than it costs to serve they have a potential path to profitability.

Training costs are fixed at whatever billions of dollars per year.

If inference is profitable they might conceivably make a profit if they can build a model that's good enough to sign up vast numbers of paying customers.

If they lose even more money on each new customer they don't have any path to profitability at all.

There's an argument to be made that a "return on investment by way of eliminating all workers" is a reasonable result for the capitalists.