I think the author is underappreciating end game. Understanding how drive winning pawn promotions informs much of the other strategy. This sort of thing informs when to make a trade or a sacrifice. If you don't understand it you aren't likely making good trades. The other simple idea is control of the center and evaluating your play to ask yourself how much control did you have?
I'm 1878 on lichess rapid, so slightly better than the author.
At this level (at least with my play style) the end game rarely decides games, usually one side or the other will gain a decisive advantage earlier than that.
It's obvious to me that there will become a point where I need to start really studying endgames if I want to improve forever, but it's not yet. Moreover my opponents also don't understand engames well, and engines don't play them in a human fashion, so it isn't easy to get useful practice in them.
do you play speed, blitz, longer? If you want to play expert or master level I believe you should study end game but the format you play may have some impact on how important you think endgame is. Blunders become much rarer as you play higher level players and early advantage may come down to a few 1/2 tempo win/loss moves.
