I would argue that producing the complete written corpus on which they at least intend to train (even if some is still out of reach) cost literally everything to produce.
And the monetary cost doesn't even register when weighed against the blood, sweat and tears that went into capturing the authentic experiences of real human beings, whose honest expressions are now at least in some cases getting hoovered up, ingested, and then destroyed for all eternity, for fear that this specific work is the rounding error that might give an equally immoral competitor the edge in the bicycle-riding flamingo race that is currently consuming an absurd amount of the world's creativity and attention.
And the monetary cost doesn't even register when weighed against the blood, sweat and tears that went into capturing the authentic experiences of real human beings, whose honest expressions are now at least in some cases getting hoovered up, ingested, and then destroyed for all eternity, for fear that this specific work is the rounding error that might give an equally immoral competitor the edge in the bicycle-riding flamingo race that is currently consuming an absurd amount of the world's creativity and attention.