It's 10 PM on a Tuesday in January. A customer calls your number — elderly mother in the house, no heat, temperature dropping to 28 degrees outside. You're finishing a furnace repair at another location. You can't answer.
Your phone rings twice. Then goes to voicemail.
By the time you check your phone 45 minutes later, they've already hired a competitor who dispatched immediately. You lost the furnace replacement job. You lost the potential annual maintenance contract. You lost the referral from a satisfied customer.
The reason isn't that you weren't a good HVAC tech. The reason is that you had a voicemail system from 1979 defending your business while you were doing the actual work.
// Voicemail didn't lose that job. Silence did. Voicemail is just organized silence.