There is a principle in evolutionary biology which says that the more a species is "specialized" to its environment, the more susceptible it is to becoming extinct. At first, they become very successful in exploiting an environmental niche that is otherwise unoccupied. But if that environment changes in such a way that their specialized resource goes away, t the species no longer has the ability to "generalize" back into the main environment and can't compete with other established species.
Humans are about as specialized as it's possible be because more than 90% of us are completely dependent on modern technology to survive. We live in dense population centers where food and water are supplied by complex idustrial processes. Many people live where the climate is inhospitable without energy intensive heating and air conditioning machinery. Most people over the age of 50 are dependent on modern medicine to simply stay alive and in good health.
Most of the human race survives because of an incredibly complex system of socio-political-economic organization that is increasingly based on computer technology and instant global communication. What's alarming is we don't know how stable - or fragile - this system really is. We've built it up over the last 2 centuries, piece by piece, under the assumption that everything will always continue to work.
What would happen if the internet failed? A very large solar flare could easily take it down, at least for awhile. A week without the internet would make a huge portion of the world economy grind to a halt. Thirty years ago, it would have been inconsequential, but now losing the internet would certainly trigger an international recession. How bad would it be? How long would it last?
We should probably be more concerned about answering these questions sooner rather than later.