If everyone had access to quantum computers and they were widely adopted, it could have a significant impact on classical computers. Quantum computers have the potential to solve certain types of problems much faster than classical computers, particularly in areas such as cryptography, optimization, and simulations of quantum systems.
However, it's important to note that quantum computers are not a direct replacement for classical computers in all applications. Classical computers excel at tasks like general-purpose computing, everyday computing needs, and running traditional software. They are also more mature, stable, and easier to use than quantum computers at this stage.
Quantum computers, on the other hand, are still in the early stages of development and face numerous challenges in terms of scalability, stability of qubits (the basic unit of quantum information), and error correction. Quantum computers are currently best suited for specialized tasks that can benefit from their unique properties, such as factorization, quantum simulation, and certain optimization problems.
In the foreseeable future, it is more likely that classical and quantum computers will coexist, with each being used for tasks they are best suited for. Classical computers will continue to be the workhorses for general-purpose computing, while quantum computers will tackle specific problems where they offer a computational advantage. Therefore, it's unlikely that classical computers will become completely obsolete even if everyone had access to quantum computers.