The reason it matters is that if they are making a profit on inference, then when people use their services more, it cuts their losses. They might even break even eventually and start making a profit without raising the price.

But if they're losing money on inference, they will lose more money when people use their services more. There's no way to turn that around at that price.

It is called sunk cost. The marginal cost is what sets the lower limit. They will always be able to sell at the marginal cost of inference.