As "rescently" as 2014 I as involved with an old computer, controlling a pre-processing stage for a high volume composite casting factory. It turned out the computer had a modem and was connected with its own phone line. It also had Norton pcAnyware for remote operation.

The computer had been running since at least 1992. No one remembered ever getting remote support, so I left it disconnected just for good measure. If anyone had actually wanted, I think you could have done a decent amount of damage using that. Especially since no one knew how and what the software on the computer did anymore. :)

The landline network in Finland is currently in the process of being taken down. I suspect the amount of modems connected is minimal.

That sounds like a terrible idea. Taking apart a useful infrastructure, with unlimited potential for adoption, for purposes we don't know about yet. They took apart most of the rail network across Canada, especially the smaller rural links. And sold the land. Imagine trying to recreate an efficient communications system in the future, and trying to purchase right of ways to interconnect all the villages and towns across a 5000km wide country.

The guys, who removed the telephone poles and the wires in these parts, mentioned they paid the local power utility around 40€ per year for each single pole shared with power lines.

Mind you, we're talking (mostly) disused old copper wires, with signal quality too poor to deliver more than a few mbps over ADSL, and most of the country is covered by a very well-built 4G network delivering 10+ mbps pretty much everywhere.

I agree it's sad to see working infrastructure being taken down, but everything was privatized in the 90's/00's and the new network owners have no incentive to keep paying for its upkeep.

What good do some relatively poor quality phone lines do when we have much better coaxial and fiber around?

The one advantage is that the old phone lines have been proven to be very reliable through a lot of times where something like a 4G connection hasn't. I used ADSL as a backup for times when 4G was unreliable, like extreme weather situations. On the other hand, once line noise reduces your speed to kbps rather than mbps, they're also of limited use in this day and age.

A fax machine uses a modem of sorts, just with one specific protocol and purpose.

I can't find anything about how WarVOX differentiates modems from fax machines, but I wouldn't write them off right away.

It is based on peak frequency, you can visually see it here: https://speakerdeck.com/hdm/derbycon-2011-acoustic-intrusion...

IIRC (it has been a bit), there was a specific frequency only used by modem negotiation but not fax machines (3150?).