I don't believe they are incompetent. Do you?
Investing is won by playing the right game.
The money today is in Tech, not cigar butts.
How much does it pay to hurdle the two bars and what are the chances of doing so?
1. Returns are what matter, not edge.
2. Your edge is reflected in your decision to buy a Tech index over individual Tech companies or any other other-than-Tech investment.
So why didn't they buy when Tech swooned last year?
They'd identified the Tech they like (Amazon, Google, etc.), they had the cash, valuations were attractive, and they could have bought in significant size.
Not a good reason:
Warren Buffett Missed The Opportunity To Invest In Amazon Early, Says 'I Blew It' And Was 'Too Dumb' — Now He Refuses To Invest Today Saying, 'I've Probably Got So Many Psychological Problems With The Fact That I Didn't Do It That It's Very Hard to Do It Now'
https://finance.yahoo.com/news/warren-buffett-missed-opportunity-invest-165456527.html