So one of my thoughts is maybe AI makes this more viable. You continually refactor the code base. Often when you start something you do not know the correct abstractions anyway - so vibe-code it.
Then once you have the kinda-sorta prototype, do a full rewrite, try to do component modules with interfaces.
(maybe do multiple rewrites depending on architecture complexity)
Then incrementally improve the software quality of each of the components.
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My thesis in this is that the cost of a refactor has dropped precipitously, LLMs are really good at doing translations, and are pretty good at finding good abstractions if you work them a bit. It is also much faster, becuase in your refactor you try and focus on the big picture and interfaces, and yolo the components... Make sure that they work, but if there is a particular edge case you can fix it later.
I don't know for sure, but I am testing this out and am halfway through a rewrite of a large project into rust from c++ (second step from above) - I am mostly vibe-ing the components, But am paying a lot of attention to the interfaces and layout.