Seems one of the main advantages is higher density of conductors and connectors compared to a PCB. Aligning those dielets with micrometer precision would seem to require equipment out of reach for the hobbyist. And then bonding them, while they don't use solder but rather temperature and pressure, again with such small connectors I guess the line between bonding and destroying the thing is very very fine. Again requiring specialized and presumably expensive equipment.

First of all, I'm no expert (at all, I stay firmly on the software side of things) but here's my 2c:

I'm going to guess that when PCBs were introduced, you couldn't get them for a couple of dollars from China either.

These kind of things tend to become cheaper over time, as manufacturing, competition (newer or competing components) and availability grows.

So I assume it's at least possible that at some point, a few decades from now, they're cheap :)