By the early nineties it was know that a quantum computer could be faster than any classical computer for certain problems. Nonetheless these observations were largely driven by academic curiosity. There was not much motive for people to spend lots of money or time trying to build a quantum computer.
This changed in 1994 when Peter Shor, a scientist working for Bell Labs, devised a polynomial time algorithm for factoring large numbers on a quantum computer. This discovery drew great attention to the field of quantum computing.