OK so the responses seem to boil down to this. My question is rather why that list cannot live in a globally distributed database inside thousands of DNS server

OK so the responses seem to boil down to this. My question is rather why that list cannot live in a globally distributed database inside thousands of DNS servers, everywhere, operated by ISPs and volunteers. Sort of like now but every server would have a near-complete list of all domains that have no syntax or schema. I guess the infrastructure costs would be higher, but what are other downsides? It definitely wouldn't be possible at the time of creation of DNS, but I can't see why it wouldn't be now.