Thus, for most people the best way to invest is dollar cost averaging into spy.

Yep. I'm educating one of my daughters and some other folks about investing, or at least trying to.
It's a hard thing. Is it worth being exposed to mechanical investing? I don't think so.
Stock market stuff is such a distraction that usually it seems better to not be bothered by it.

On the other hand, a great many folks just index and dollar cost average into SPY.
I'm curious what percentage of overall assets is invested this way.
The forward longer-term expectation for SPY return is somewhat bleak, given the current high valuation and concentration in a few companies.
So, personally, I find it hard to recommend it as a strategy. RSP or broader indices make more sense, on paper anyway.

On the third hand, we are entering an age where the large companies have the inside track.
Things like AI and quantum computing are likely going to be the domain of those huge companies like GOOG, AAPL, MSFT, META, AMZN, etc.
Maybe their valuations and multiples (and SPY) can continue to grow unabated for another decade or two.
And other strategies will continue to pale in comparison.


Mark