It's all about the Mindset of a person. A strong Will and a Strong Mindset would take you to places and Heights you you've never Imagined.
When it comes to your Questions: Yes we can like without Personal Computers, Smart Phones and Primitive Technology. People are innovators and Opportunity Seekers so in case Smart phones and technological devices go out of Demand. People will find Invent and Find out other things Which would have the Possibility of being More Stronger and Way better than the technology that we are using at this Moment.
Social Media, Internet, E commerce and Many other Beautiful things are a Big Part of our lives now. No one ever imagined that Freelancer ( Youtubers, Social Media stars, Internet personalities ) Could accumulate a Huge Wealth by Using their Creativity and Innovation, Entrepreneurs could Build an Empire and Attract a Massive Following for their Products and Businesses.
I Come to a conclusion that People should be "Flexible" in their lives. We should always learn to Switch Lanes, Carriers, Take decisions and Learn New things in Their Life's and I believe that the World wouldn't come at "Stand Still" If one thing disappeared! As I Said "People are innovators and Will Keep On Seeking for Better things replacing the Old and Outdated Ones" .