I’m seeing more retro-style tech spring up for kids. We just got one of these for the kiddo: https://tincan.kids/ and have found out several other parents have them so there’s a small but growing network of kid landlines forming.

Even without purpose-built things like TinCan, most "landlines" these days... aren't. My parents' house is wired for telephony, but the backhaul is 5G. A box in the house serves as the uplink between the 5G network and the "landline" phones throughout the house.