Tiny computers are everywhere. Even a wifi sd card is actually a full Linux system. More and more tiny systems (SOC) have things like wifi, bluetooth, even LTE connections built in by default. It's not just for user functions either; a wireless port is very convenient for technicians doing maintenance or a repair center looking for a fault.
Manufacturers will today often make "separate" models in part by disabling or enabling functionality in software. And the more you can reuse components the cheaper it gets. So a maker could have one standard SOC for their entire range of products, with all kinds of stuff integrated and nobody but the system designer even knows it's there.
I bet it will become really common with equipment that have no business being online, and where neither the seller or buyer even realizes you can connect to it remotely, or that it has open, unfixable security holes.