Cyber attacks and closed networks.
I have been thinking about this for a while, in part because my job is impacted by it.
When dial-up was the only option for getting onto the Internet corporations and governments were the only ones who could afford to purchase T1 and faster network services from the Telcos. Because of the nature of these networks being private they were mostly secure from hacking. Some had dial-up access for workers while others would just pay for a direct drop to an employee's home if their job required the access.
Today, almost everything and everyone uses the Internet and some sort of VPN technology instead of dedicated data connections. You can encrypt the contents of your packets but the routing information can't be encrypted. Once an interested party decides you are worth hacking it is only a matter of time before they get in.
I strongly believe that if government and corporations would go back to using dedicated connections and stop trying to save a buck by using the Internet a lot of our cyber security problems would vanish overnight. You can't hack a system you can't access.
Obviously many consumer side functions have to reside on the open Internet. What good is Amazon if you need to pay for a direct connection to it? Email is also something that requires Internet access to be useful.
I realize that it is not a perfect solution (Stuxnet) but I do believe that most businesses and government agencies would reap benefits that outweigh the costs.