Quantum computers, when/if they arrive in a decade or two don’t replace silicon chips. They add to them in massive, super cooled data centers. Phones, laptops, desktops, car computers and zillions of consumer electronic devices will still be using something closer to silicon chips and not quantum computers.
Not only do they have to get them to reliably work and be efficient, they have to compete on tasks they are good at with the server class chips that are a decade or two down the road.
Mike