You make a valid point there Marg, but telecom providers can only do so much. For example, I saw one of those investigative TV shows recently. They traced scam callers to the UK back to India. What the crooks were doing was somehow dialling through some device that gave a UK number to the receiver.
You might wonder where these odious individuals get our information, fact is, we give most of it away, quite freely, not just on social media sites but on simple things like on line purchases. When you buy on line you have to give an email address, ever wondered why?
The way to deal with it is to believe nothing. Recently I had a letter from my credit card company asking me to call them most urgently because they believed that my card had been compromised. Being suspicious, instead of calling any of the numbers given in the letter I called the number that's on my card and asked the customer services if they had sent me a letter. It turned out to be true. They told me the problem, cancelled my card and issued me with a new one. But it could so easily have been a scam.
Admission time, that finger dial phone was issued to me at my first address back in 1968, I bought it from the phone company, after privatisation for the princely sum of one pound. It still works but like everyone has said, it's important to know the incoming call and to that end the old phone is linked to a modern one. There's another good reason to have a modern handset, finger dials are useless for voice menus. When asked to press one for the money, two for the show, doing that with finger dial just cuts you off.