"Pick a diverse basket of unhyped, sane stocks" sounds like "my trading strategy" because it's not at all specific or repeatable. It also just sounds like a homemade index fund that never rebalances.

If it were really that easy, individual investors and professional fund managers wouldn't lose to hedge funds in the long run for all of the history of index funds. You'd also see at least some evidence of skilled stock pickers at, say, hedge funds, and you don't.

In gambling, a few people beat the house. That's a guarantee of probability. In aggregate, the house always wins.

You have a point, but by that reasoning it's pretty much impossible to prove the contrary. Long term investing in good companies, that are 'cheap' works. Not easy to prove though.

2 of my favorites on this topic:

Warren Buffet's "The superinvestors of Graham-and-Doddsville" - https://www8.gsb.columbia.edu/sites/valueinvesting/files/fil...

Joel Greenblatt "Little book that beats the Market" - https://www.magicformulainvesting.com/Home/AboutTheBook

Probably not easy to do that. Possible I would believe.

Today's "unhyped, sane stock" is tomorrow's train wreck, as businesses and industries changes, leadership changes, etc.

You can pick a good stock in the short (2-3 year) terms if you know their industry and their business well enough to really believe in their strategy. But it is difficult to have that level of knowledge on a broad enough base to build a stock portfolio out of it. It is better the just let the index funds be your base, and maybe dip your toes in those rare stocks where you do have deep knowledge and confidence.