The idea that a decentralized fault tolerant network is such a novel concept that it required a government to think of it doesn't make a whole lot of sense. Even the telephone system is decentralized. There are decentralized fault tolerant systems all around us as examples.
It doesn't require the government to think of it, it requires the government to implement it. It would be a massively stupid decision from a business point of view to implement the Internet as it exists today. There's much more money in centralized networks. I think this should be obvious from the fact that (1) at the time all commercial companies were building centralized networks and (2) today text messages cost upwards of $1k per megabyte. The only reason why the Internet is architected the way it is today is because of government funding. One the government set the Internet in motion towards a decentralized, packet switched network, it could not be overcome by commercial companies.