It's a strange liability that every trusted CA is authorized to sign certificates for every possible domain, even ones it has no right signing. It would make more sense for them to be limited to a set of TLD/ccTLD.
Isn't that the purpose of CAA? You can choose which CAs can sign a cert for your domain?
> even ones it has no right signing
They have that right though? There is no monopoly to single CAs for a given domain.