Thing is, it's getting pretty cheap to build radios into devices, and companies are doing that and bridging them to whatever Internet connectivity they can reach, not just your own. You don't necessarily have to personally plug something into an Ethernet socket to make a device Internet-connected.

From back when Amazon Sidewalk was rolling out:

https://www.statuscake.com/blog/what-is-amazon-mesh/

This time, however, the big news is Amazon mesh, a network to connect users and their devices. The tech giants have called this project Amazon Sidewalk+ with the idea first being made public back in 2019 where they announced they wanted to extend and expand the connectivity of their customers.

Why did Amazon do this?

According to Amazon, the main reason was to provide a better service for their customers whilst using their devices. Although there has been some backlash by those in the safety and security space, the idea seems to be very safe and simple. 

How will Amazon mesh work?

The Sidewalk project will create a network mesh between all the connected devices so it can increase the connection field around the devices. It will be able to do this by using Low-energy Bluetooth and 900MHz radio signals to pass data with the connected compatible devices. By doing this, the network can extend the reach of the signal and thus it will be able to cover a larger area to allow devices to connect. 

Here is an example of how this will work: imagine if you have a compatible device at the end of your garden such as a light which you normally can’t control with your phone. With the extended network, that light could connect to a neighbour’s device and by doing this it will be connected to the network, and you will have the ability to then use your phone to control the light.

There has been some concern regarding how much data the network will use for those who agree to be part of it and Amazon have estimated that the data usage could be around 400-500mbps a month. For most people, this is such a small amount that it won’t even be noticeable.

How can the mesh network be used?

Another use for this mesh is for users around the network to connect and possibly use the mesh to perform other tasks such as a Ring doorbell (Amazon-owned) to be installed in the part of the house where the usual Wi-Fi signal doesn’t reach. This provides customers with a great alternative to the far more expensive Wi-Fi extender mesh products on the market.

As is normal in situations like this, many users are concerned about the security of this project. According to what Amazon has released regarding how it will work so far, there will not be any security concerns as the connections will not identify which device was connected meaning that if your Ring doorbell extends the network to a nearby device, the system will not mention that this device was connected to that particular Ring doorbell. However, people need to be aware that Amazon itself can collect this data and the way the users interact with the network.

https://www.theguardian.com/technology/2021/jun/01/amazon-us-customers-given-one-week-to-opt-out-of-mass-wireless-sharing

The feature works by creating a low-bandwidth network using smart home devices such as Amazon Echoes and Ring security cameras. At its simplest, it means that a new Echo can set itself up using a neighbour’s wifi, or a security camera can continue to send motion alerts even if its connection to the internet is disrupted, by piggybacking on the connection of another camera across the street.

But the company’s plans have caused alarm among observers. Ashkan Soltani, a former chief technology officer of the US Federal Trade Commission, told the tech site Ars Technica: “In addition to capturing everyone’s shopping habits (from amazon.com) and their internet activity (as AWS is one of the most dominant web hosting services) … now they are also effectively becoming a global ISP with a flick of a switch, all without even having to lay a single foot of fiber”. The feature may also break the terms and conditions of users’ internet connections, which do not allow such resharing, warned Lydia Leong, an analyst at Gartner.

Users can disable Sidewalk in the settings section of the Alexa or Ring apps, but have until 8 June to do so. After that, if they have taken no action, the network will be turned on and their devices will become “Sidewalk Bridges”.

Amazon is not the first company to look to create such a network. Apple has taken a similar approach with the company’s range of AirTag item trackers, which can connect to the internet through any compatible iPhone they come into contact with, not simply their owner’s. And BT, through a long-term partnership with Fon, ran a service from 2007 until 2020 that allowed broadband customers to share spare bandwidth in a public wifi network.

When you have companies creating their own radio networks, they can use someone else's Internet connection to move data.

For expensive devices, like cars, it also makes economic sense to have a dedicated cell modem and service phoning data home. But it's not the only route.

Point is, you don't have a monopoly over granting your devices Internet access any more.