David, if you're not a teacher (and have never been one?), you can't begin to argue the issue with any insight.
Gotta admit, I stopped reading your post there.
Following that logic (?), do you also hold that if you've never played professional sports, you can't possibly be an insightful professional sports commentator, writer or analyst? Or is that somehow different? And if so, how?
Lemme know so that I can wash my brain of anything I ever learned from Vince Scully, Bob Costas, Tom Verducci, Paul Zimmerman...
Me, I went to school for ~20 years, have two relatives (both with PhDs) who taught for years, am married almost 45 years to a retired school teacher, live in a neighborhood overstocked with retired school teachers, and have audited the books of about 20-25 schools. But, OK, I've never been a teacher. Do I, and others with similar bios, also NOT have any insight on the issue?

I never listen to any predictions. As a trader I only pay attention to prices, charts and trends lately and NOW. They tell me in real time what the market is doing. In the last 10 years I was invested at 99+% of my money at 97% of the time. The key for me is to invest all my money all the time and no cash, BUT, when risk is high to be in a high % of cash for days to several weeks.

... if you're going to take duration risk, take duration risk in your equity sleeve, not in your fixed-income sleeve. Duration risk in equities is really cheap, given how attractive utilities are priced today relative to investment-grade or Treasuries

But you can't outperform by 400 basis points a year or 300 basis points per year if you have 100 stocks. It's very, very hard to do that. You really need to be a little more concentrated.

I think what drives in many respects the multiple companies is a little bit supply and demand. So, the reason why this 13% of the S&P 500 that I call GARP, trades where it does, and it should trade higher, is that a value manager will often look and say, Well, these companies, they trade for 10% or 20% premium to the market, that’s too expensive, so I can't invest in those stocks. Growth manager says, you know what, these companies, they're only growing organically like 4% or 5% organically. I want to own companies that are growing 10% organically.
So, in many cases, there's no natural buyer for these companies. So, that depresses their valuation to a level where, again, if you think about the market, the market, typically, in non-recession years, grows earnings at 6% to 7% kind of clip, gives you a 2% dividend yield. So, for a small premium to that, which you'd able to generate, is find the companies that are growing earnings at 10% plus, maybe a little bit more dividend yield, and have much less downside risk, because there's an inefficiency. The two big market participants kind of shunned these companies a little bit. So, what happens is, over time, they just compound wealth, and in many cases, the market becomes a little bit smarter over time and says, Oh, it used to trade for 18 times earnings, but it's actually a really good company, and you should trade for 20 or 21 times or 22 times. So, you get the compounding of the earnings and the dividend and usually, like the multiple expands.

It turns out Staten Island Chuck is, on the whole, more reliable than Phil of Punxsutawny, if you look at the past years data:
How Often Are Our Local Groundhogs Right?
Based on 24 predictions since 1992, as measured against data from the National Climate Data Center
[Bar Chart]      Punxsutawney Phil 43%      Staten Island Chuck 65%