There's only 1 set of power lines going into each building, yet there are multiple providers/sources of electrons in the grid.
The difference being that it is impossible to differentiate between the electrons you take off the wire, while it is critical that you get the same packets your ISP is putting on the wire for you and not just any packet that happens to be coming by.
That means that when an energy provider is "broken" and not putting electrons onto the distribution grid, it is a problem that that provider and the owner of the distribution grid both are very interested in solving (your payment through the distributor goes to the provider and the provider isn't). If your ISP is broken and not putting the right packets onto the distribution medium for you, the distributor doesn't care and probably doesn't know, YOU care and YOU have to deal with the ISP -- who would then blame the distributor who will blame the ISP ...
In other words, alternate energy provides can break and you'd never know it but those who have to fix it will. If your ISP breaks, YOU'll know it, but probably nobody else will.
Back in the day, there was only 1 set of phone lines into each building, but you could get phone services from multiple local or long-distance carriers.
No, "back in the day", you got to pick one local phone service and they were tied to one LD. Divestiture change the latter because the LD services were put onto the one local telco's wires to the subs at the CO or above and the LD service didn't need physical access to the copper to your house. In fact, which LD you used became an entirely switching-based question, and you could use access codes to pick a different LD provider every time you called someone. A different local provider would need that physical access, and that didn't happen, because the switching system was hardwired to your copper pair. Your phone talked to the local telco switch and you couldn't say "connect my pair to someone else."
We need to separate IP infrastructure (1 set of fibre cables into each building) from IP services (multiple ISPs, IPTV, IP-whatever companies).
And if you think getting something fixed is difficult now, just wait until there are three or four different companies involved in your one broadband connection. It's hard enough now to really determine where a packet loss problem is happening, just think what it would be like to determine if Comcast (the wire) was dropping packets or is it Frank's Hometown ISP and Dry Cleaner that's messing up.