Fundamentally modifications to TCP are necessary

In practice it just doesn't scale, the overhead of letting the routing tables get that large just doesn't work at acceptable speeds.

Someday this may change.

It has changed for phones. It used to be that the area code and first three digits of the number routed you to specific buildings and then the last digits routed you out from that. so while there are still large chunks of landlines that mostly follow this model, phone number portability and cell phones make it so that any phone number can appear anywhere on the network.

now, the phone system only needs to find this to setup the conversation, not for each packet. This is the "smart network vs dumb network" discussion from above.

Given that the "smart network" of the phone system now tends to run on top of the "dumb network" of the Internet, I think it's pretty clear that the Internet has shows itself to be far superior

If you think about it, the Internet already has the layer of indirection you are talking about, DNS. The problem is that looking things up in DNS is far too slow and updates far too infrequently for it to be used in routing decisions for every packet.