I worked for a major telco in technical support/customer service.

I saw numerous security issues, and when I brought them up, with solutions to improve the service for customers, I was informed the the company would lose money.

Scammers are big customers for telcos, and when they get caught, and banned, they come back again and pay a new connection fee and start the cycle again. Scammers also enable feature upselling, another way to profit from not solving the problem.