Depends on the size and complexity of the problem that the system is solving. For very complex problems, even the most succinct solution will be complex and not all parts of the code can be throwaway code. You have to start stacking the layers of abstractions and some code becomes critical. Like think of the Linux Kernel, you can't throw away the Linux Kernel. You can't throw away Chromium or the V8 engine... Millions of systems depend on those. If they had issues or vulnerabilities and nobody to maintain, it would be a major problem for the global economy.
companies have been abandoning products for decades, and shuffling ongoing support onto other entities. nothing has to be "thrown away" as you keep suggesting.
