Phone calls were dying, but phone spam sure made the demise that much faster. Pretty amazing that nobody in that industry had a vested interest in combatting it.
Phone calls (mobile or landline) should never have been allowed to drop below 1¢/min at whole-minute or larger granularity. With absence of industry will to keep costs there, government should have taxed it. Any lower (esp. granularity) & it's all spam & scams.