Junk calls supports the telecom industry in the same way the USPS is supported by junk mail.
Large companies delivering unwanted and potentially fraudulent calls buy tens and tens of millions of dollars in telecom equipment each year to make their ad campaigns go. As well as a much, much larger amount, probably hundreds of millions, to lease high capacity lines to connect to the public switched telephone network.
Similarly, while the Post Office decries the amount of junk mail they have to deliver, the truth is that the USPS would be severely hurt economically if the bulk mailers weren’t mailing. Actual responses hover around two to three percent in the junk mail business, figure the same with robocalls.
In either case, don’t look to relief soon as both groups want to keep their income coming in. Just another example of industry saying one thing and then doing another.