If the attacker bgp hijacks the record target they need to also bgp hijack the authoritative server that holds the TLSA record (which the client could verify during an attack).
If the attacker want to bgp hijack the authoritative server they will need to bgp hijack the TLD name servers that holds the DS posts for the authoritative server.
If the attacker want to bgp hijack the TLD name servers they will need to bgp hijack the root server that holds the DS posts for the TLD name servers. This they can't do because the root servers keys are hard coded into revolvers.
