Talking about symmetric links only makes sense when you think about backbone providers. When you're talking about residential ISPs, their traffic is by default

Talking about symmetric links only makes sense when you think about backbone providers. When you're talking about residential ISPs, their traffic is by default asymmetric (residential customers consume bits and request much smaller numbers of bits), but that doesn't mean the value is gained only by the person sending the bits, it's also gained by the person receiving the bits. This doesn't actually make any sense. Let's say everyone decided "No, we're not going to peer with Comcast because it's not in our interest to do so". What would happen? Do you think someone would step up to the plate and say "Hi Comcast! We're going to pay you for the privilege of being your transit provider!" And yet if the asymmetry story is to be believed, it's Comcast that should be paid by a transit provider, right?