That analogy doesn’t work at all because the Sow produces a finite (and rather small at that) number of piglets over a given timespan.
It’s more akin to you getting a piglet/sow elsewhere. Now your piglet/sow need is satisfied and you won’t buy anything from this farmer.
(Edit: And even then you took that piglet/sow away somewhere else, reducing supply there, which will make it more likely for this farmer to get a sale in the future.)
That analogy doesn’t work at all because the Sow produces a finite (and rather small at that) number of piglets over a given timespan.
It’s more akin to you getting a piglet/sow elsewhere. Now your piglet/sow need is satisfied and you won’t buy anything from this farmer.
(Edit: And even then you took that piglet/sow away somewhere else, reducing supply there, which will make it more likely for this farmer to get a sale in the future.)