To go into further detail about systemic investing:
There have been experiments like the turtle traders ^ 1 who applied "trend following", used today by many CTAs on exotic markets. For this, an investor taught some people his strategy/rules, gave them his money and they've shined for 40 years. The fundamental strategy still works today (updated). Fundamentally, it's a method to ride momentum in different ways (e.g. crossectional.) Hedge fund managers like Rzepczynski, Cem Karsan, Alan Beer... Richard Brennan is the most insightful of them who shares his methods freely. N.b. trend following doesn't work well in stock markets, but flourishes in Mexican rate swaps, orange juice futures, London sugar... combined in ensembles.
Traditional value investors, building on the Intelligent Investor, have always done well over samples above a few years. (N.b. Warren Buffet hasn't been a value investor for a long time, because he has too much to manage. He was strongly inspired by Fisher's Common Stocks and Uncommon Profits, which gave us the concept of "growth stocks".) (N.b. 2, value investing ETFs are mostly terrible, fundamentally not investing in value stocks due to their structures.)
Carisle's Acquierer's Multiple is the most recent development in systemic value investing (he also runs an ETF or two along these lines). "Magic formula investing" even holds up too!
In the mining space, you also get discretionary (not purely systematic) investors like Rick Rule openly discussing their methodologies, successful for decades and decades.
Here’s an interesting paper ^ 2 (exec summary pages 5-6). Note that 70% of underperformance is due to investors withdrawing funds during times of market crisis. Fund fees also drive the majority of underperformance. N.b. most wealth managers can't legally follow such strategies because of the prudent person rule. They are legally forced to underperform typical indices - and the majority of research has focused on them, distorting the data pool.
[1] https://www.investopedia.com/articles/trading/08/turtle-trad...
[2] https://wealthwatchadvisors.com/wp-content/uploads/2020/03/Q...