Of course we can write code that is buffer overflow free and safe and secure in every other manner too. We just can't do it when prioritizing new features, writ

Of course we can write code that is buffer overflow free and safe and secure in every other manner too. We just can't do it when prioritizing new features, writing to a spec defined by committee and having limited resources, with thousands of competing interests. For a nuclear power plant where focus is on safety first and the code in the critical paths would be limited and the spec defined then and there for verifiability, the system could probably even be proven correct.