[1] I have no idea what they're called now. There's a huge chain of acquisitions. They may have stopped serving this market, but someone still is.
It does look like these may be Starnet/Megapop numbers, based on the panix.motd.megapop newsgroup mentioned on Panix's website. I did spend a minute trying to find who (if anyone) is steering the remaining dregs of Megapop, but I didn't make it very far.
I'm not interested in dialup data services at all at this point in 2026. I have no remaining means with which to use such a thing. The last cell phone I had that could act like a modem got retired in 2009 and the last time I had a dialtone in my house was 2010.
But if I had to guess, then I'd guess that these time machines are still operational.