[Comevius]

They became cost effective in a few years. The average price per integrated circuit dropped from $50 in 1962 to $2 in 1967. By then Moore's Law was established. At the end of the decade we had hundreds of transistors on a chip. At the early 70s we already had general-purpose microprocessors with thousands of transistors.

Quantum computing is being researched since the 1980s without a theoretical understanding whether they can be built at a practical scale.