For decades, the Telcos did nothing about unwanted calls. If anything, they encouraged it because they were able to often charge by the minute. All of this was possible because there was absolutely no competition. You signed up with Ma Bell, or you didn't get phone service. It literally took an act of Congress to force them to let you buy your own phone instead of leasing one of the two models (standard or trimline) offered by the Phone Company.
Nowadays, the old-fashioned Telcos are starting to feel the pressure of competition. People are ditching land lines in droves. They can actually choose a carrier now.
Guess what! Suddenly the Telcos are starting to remember they they have living, breathing, unhappy customers. FINALLY they are starting to innovate. Unfortunately, it's a bit too late.