so penalties for telcos have to be higher than they earn from scam calls.

2-5% of scams succeed but penalty should be there accounting for 95-98% that did not succeed.

IANAL but I know failed attempt at robbery or murder is also prosecuted, failed attempts at scam are not, because people just hang up and move on. Then the reality is society doesn’t have enough resources to deal with "scam attempts" - well we have to focus on murder attempts an plain robbery