it's amazing what you can hack into nowadays when you have the technical acumen to do so.
Not the phones and call recordings at a trading company. I know from first hand experience the level of security and audit log that goes into those platforms because, well, y'know.
Encryption / decryption happens at device level, not transit, so the only way to hack into a live call is by physically tapping the receiver. Recordings are encrypted at rest and decryption/playback are security controlled and captured in audit log, often with escalated alerts.
No one is overhearing the CxOs of a trading company on calls with the White House because they're a junior tech in the company.