I read (yet) another article earlier this week about the imminent death of Plain Old Telephone Service and how VoIP has developed over time to become just as resilient and reliable as the original Public Switched Telephone Network. Perhaps POTS will eventually be relegated to the dust bin of history, but from a practical point of view the fundamental argument against POTS and for VoIP-type services is really more economic than a question of reliability.
While VoIP protocols and fiberoptics are these days truly equal to POTS when it comes to call quality and reliability under picture perfect circumstances, POTS still has a lot going for it when the chips are down. In a world where the electric grid has 100% uptime, there is no such thing as weather and computer networks suffer no disruptions, perhaps VoIP is the perfect product to have no backup for. Of course, the real world does not exist within this type of environment and at the moment POTS still provides a relatively inexpensive fall back in the event that things get "real".
Let's take a relatively recent, real-life example of how having POTS as a backup or primary line can literally be a lifesaver. In late 2015 a number of vandalism incidents in Northern California left as many as 100,000+ internet and wireless customers without any voice or internet connectivity. The wireless carriers had all of their eggs in one basket. No local switches. All calls were backhauled out of the area via fiber and when that failed every single wireless carrier went dark as well. No "circuits busy" recording. No 611. No 911. No bars. Just silence.
Those who used VoIP based services, including every major CLEC and remote hosted PBXs also went dark. With no local switching facilities all customers were effectively dead in the water. No 911 or emergency calls. No reaching an operator. No way of reaching their service provider whatsoever. You could not make a call across the street or even within the same office in some cases. Without the ability to make or receive phone calls or complete transactions via credit card terminals or ATMs, quite a few local businesses were forced to shut down entirely for more than a day in some circumstances.
However, during these incidents those who still had access to a POTS line could make calls within their offices, across the street, reach emergency services and contact other POTS customers in most surrounding towns. Local central offices were still interconnected via the PSTN and to my knowledge no disruption to voice services other than out-of-area long distance calls took place. A landline was worth its weight in gold that day, especially for anyone unfortunate enough to need to dial 911.
For businesses, even having a single POTS line as a back-up literally meant the difference between staying open and sending all of their employees home for the day. Obviously, it was a very bad day for pizza delivery services and similar companies that didn't want to spend that extra $30 a month on having even a single POTS line as a backup.
Things can go similarly as bad for digital services when there is flooding, electrical outages, internet disruptions or other unforeseen circumstances that can disrupt just about anything but a traditional landline.
While I am not advocating going back to the stone age and moving all of one's lines over to copper, for businesses in areas that still offer it and depend upon phone service for mission-critical operations, not having at least one POTS line as a back up seems foolish at best and reckless at worst. VoIP and remote PBX-type services are wonderful 99.9% of the time, but at present POTS is still incredibly cheap insurance that justifies it's price tag of around $1 a day.
Perhaps one day carriers will spend the capital it takes to make digital phone services as reliable and resilient as POTS service is today, but don't bet on it. As long as consumers continue to choose cheaper prices and convenience over increased reliability you will not see any companies willing to make this type of investment. Copper may not be the future of the industry, but for the moment it still has its place for most businesses.