In the future, someone invents a time travel machine and makes it so inexpensive that just about anyone can afford one. The first people who choose to go back into the past return with casualties and diseases because life is so much worse. Consequently, people decide to go into the future because everything will be better due to technological improvements.
In the end, everyone is going into the future on their time machines and no one is working on anything.
I'm just an idea man. I'll leave it to you to write the rest of it.