Socialism

We have not "allowed" corporations to get big - they always will, that's the inevitable outcome of capitalism. Being bigger is always more economically effective, and capitalism is all about economic efficiency as it's direct means to produce more money. The corporations of today were literally predicted in the 19th century, and look where we are.

Capitalism cannot exist without the premise of consolidation and expansion - it is the driving force that motivates people to do something in a capitalist economy in the first place.

As wealth and, essentially, power consolidates into fewer hands, we face the same challenges - only now we have to deal with completely unelected authority that owes us nothing. Their downfall can have rippling effect on the entire economy, causing insane crises which, in turn, can quickly spiral out of control as markets are prone to vicious circles. Quite a few capitalist economies faced severe crises for seemingly stupid reasons.

Socialism, on the other hand, doesn't have to revolve around profits and monopolization. While economic efficiency that comes with centralized control is certainly hugely beneficial, we can build economy in any other way in order to make it more robust should we want to.

Soviet Union had telephones, and they were commonly used by everyday citizens - at home in cities, and through telephone boxes in villages and remote areas. I don't know where you take that from.

As per Internet, Soviet Union was developing a similar technology (OGAS, essentially dial-up Internet) since 1962. At first, it was designed to connect factories to better allocate resources (something that is now done by corporations and their logistics departments) - something that stemmed from the limitations of the time - but nothing stops the technology from being used on a residential scale, as fairly modern telephone lines were already there and new cables weren't a big issue.