If I spent the last 20 years allocating 90% of my savings to SPY, and the remaining 10% in a large-cap tech focussed index, I’ve outperformed SPY. Is that dumb luck or is it a pretty trivial implementation of a sensible investment thesis?

There’s nothing magical about some committee-curated collection of 500 US-only equities which means it outperforms every other option ipso facto.

If you were talking about a normal person actively managing a portfolio I’d be more inclined to agree.