Down a goal, late in a game? Those situations are crucial, and you should put your BEST players on the ice in crucial situations, because they are the ones most likely to succeed.
That is why you put Crosby on the ice. That is why you let Michael Jordan take the shot, that is why you put your best pitcher on the mound. The best players are the ones most likely to perform in a key situation, because they are the ones most likely to perform in all situations.
Clutch is a myth, its a narrative, just like character. Give me talent.
As for your examples... those are hypotheticals. The player who goes 10 for 10 and 0 for 10, don't exist in real life professional sports. Find them for me and then we can talk.
But here is an example of an actual player i know of.
Alex Rodriguez was a great player. However many called him a choker cause he had a near mendoza-line batting average over the 2005, 06 and 07 playoffs with the Yankees. Fans in New York wanted him benched in the playoffs. The next time the team made the playoffs, the manager played him despite the fans callin for his head cause the guy isn't clutch. Then in 2009, he hit over 400 in the playoffs as the Yankees won the world series.
What happened? Why did he stop choking? The truth is that he didn't discover some secret of being clutch that year. He was simply always a great hitter, but one who was unlucky to hit a slump in the playoffs. The next year he hit a hot streak in the playoffs.
The lesson is always play your best player, don't count on something mythical like clutch to make you believe some other player should be put into the crucial situation.