I fear this won't even required SIM cards. I'm worried that Apple's Find My and Amazon's Sidewalk networks are the precursors of this: They're effectively company controlled p2p networks that lets the company use their customers' internet access points like a commodity. If one customer refuses to give a device access to the internet, they could use that network to route it through the access point of another customer.

Also, personal experience: My own ISP (in Germany) experimented with some similar stuff a few years ago: They mandated use of their own home routers where only they had root access. At some point, they pushed an OTA update that made the router announce a second Wifi network in addition to the customer's. This was meant as a public hotspot that people walking down the street could connect to after installing an app from the ISP and buying a ticket.

The customer that "owned" the router wasn't charged for that traffic and the hotspot was isolated from the LAN (or at least the ISP promised that), but it still felt intrusive to just repurpose a device sitting in my living room as "public" infrastructure.

(The ISP initially wanted to do this on an "opt-out" basis, which caused a public uproar thankfully. I think eventually they switched to opt-in and then scrapped the idea entirely.)