As I'd posted this poll a week or so back, general direct-dialed telephony, a/k/a PSTN (public switched telephone networks) seem to be in trouble. I think we could be within five years of their total collapse. And no, not just land lines (already about 25% of their peak in much of the US), but _all_ direct-dialed phones: mobile and VOIP included.
The problem, as I'd written before, is paradoxically the _low_ cost of calls. This is inducing tremendous volumes of junk calls, with one ...
... though I think I've got some sense of the terrain ahead and useful lessons from the past.
Generalistic and moderated instance.