Comment There's other factors to consider (Score 1) 582
Some years ago I was listening to a radio program where they mentioned some company in Australia(?) planning to dismantle the urban POTS and replace it with something newer. But the reasoning wasn't just for upgrading: It was because they couldn't get the parts anymore.
Some of the manufacturers had stopped making the relays and whatnot that the POTS used, so the options were to convert to a new set of POTS hardware (an expensive Red Queen's race), get a huge order of compatible components custom-made (ditto), or upgrade-and-cannibalize the urban network to get them enough parts to maintain the rural POTS for another couple of decades and hope the entire system could be upgraded before they emptied their supply.