The phone service has to follow laws and contend with customer needs of all kinds. Then theres that thing called "Freedom of Speech" that puts a damper on things as well and criminals don't care about any of that. We have to do our part sometimes and not expect its someone else's sole responsibility.
People working together is what makes us civilized, so lets all help each other when ever we can.
Phone companies SHOULD be held responsible. Car companies put reasonable precautions in place to ensure a safe and pleasant vehicle. The phone companies have implemented absolutely nothing to protect consumers. If they did and the spammers find a loophole, the hole should be filled. The same as if a defect is found in a vehicle, that vehicle is recalled and fixed.
They are big business telecoms. Let their tech people figure it out... I have my own job to do and am not paid to solve their inadequate consumer safety measures. And yes they are safety measures because people are being conned by illegal activities.
People have been conned for centuries, long before there were telephones. Some responsibility lies with the consumer, such as educating themselves about various scams. Hence, this website.