Can someone explain to me why although we've known that classical physics is not a correct description of the hardware of the universe for at least 100 years no

Can someone explain to me why although we've known that classical physics is not a correct description of the hardware of the universe for at least 100 years now, we are still hooked on 90-year-old Turing Machines which cannot physically exist (they violate quantum mechanics) and whose theoretical limitations are, consequently, irrelevant.