Trying to find one rule-set by which to trade a 20 year length (where the market might show 4-5-6 different faces) is very much a fool's errand. It'll kill you, AND your account.
"Algorithmic Trading" (simply: "Rule-based Trading") is what you've described. But you're thinking that there must only be one, single, algorithm. What if you had rules by which to choose from different algo's? Or different portions in algos? A second
layer of rules? Now you're into "Artificial intelligence."
Fancy, fancy terms, for what is really just a slightly different way of thinking. ["Out-of-the-box-
spread thinking??"

Nah. It's not Bad Pun Thursday.]
So, do you, right now, expect the market to change in the next 2 years? I certainly do. So, I would like a one or two year model, for which I might trust it
for the next month. That's all. Just one little month at a time.