The US telephone monopoly AT&T was formed in 1885, and until 1956 users were not allowed to attach anything to the network.
When AT&T controlled the telephone network, they owned the telephones and rented them to the users. They also had to raise the capital to build the network and manufacture the telephones. This is contrasted to the Internet where you can connect any device running the TCP/IP communication protocol. This has led to exploding investment, with billions of users investing trillions of dollars. Even at its prime, AT&T could not have afforded that.
The first example of this edge-investment effect was the creation of the first Internet backbone network, the US National Science Foundation NSFNet. The creation of the NSF backbone network and the research that created it cost the US taxpayer under $125 million. The NSF allowed universities to connect to the backbone at no cost. That small subsidy encouraged the universities to invest many billions of dollars building and staffing local area networks.
We also see hardware innovation at the edge of the network. We connect to the Internet using PCs, cell phones, PDAs, etc. Mars rovers and medical instruments provide Internet data. People have attached scientific instruments like telescopes and microscopes, medical instruments, Web cameras, vending machines, etc. etc. to the Internet.
Note that in some cases, we are connecting devices used by people to the network, and in other cases we are connecting machines. Machine connectivity is expected to grow rapidly in the future as they begin to incorporate sensors that can detect the location and condition of a device. For example, merchandise location will be tracked in warehouses and automobiles will detect and report collisions.
The expected proliferation of attached devices means we will run short of unique Internet Protocol (IP) addresses. The need for more device addresses is one of the motivations for migration from IP version 4 to IP version 6 on the Internet. IP v6 has a longer address field than IP v4, allowing many more devices to be individually addressed.