Ask HN: What is the single top-priority software engineering problem?

If you have unlimited time and/or resources, what single software engineering problem would you address? I'm not talking about "Peace on Earth"-type problems, but rather real world practical problems facing software engineering that could be actually solved if you could pay an rationally large team of serious hackers a rationally large amount of money for a rationally long period of time. Another way of asking this is: What's the most important piece of technical debt across software engineering, that could practically be solved if we put enough energy into it?