Besides laziness being a tradition among programmers (in a good way), that kind of complex activity is going to generate tax in a lot of jurisdictions.
If you care to explain why, I’m interested. I imagine a situation where large Sum X is in ETF but gets adapted by a few little shorts. It’s still mainly the ETF in the portfolio. (Exactly this is why in my firm some ETFs are deemed too precise, since they are thought to follow the insider knowledge as well.)