You make it sound like great players have to be great all the time. That's a very modern expectation but it isn't remotely grounded in reality. Here's Zidane arguably at at his peak as an individual, months before his sublime Euro 2000 performances - up there with the greatest individual tournament in international history - against Lazio.
He gives the ball away with his first pass, falls over a few times, mishits a few shots and loses the ball a few times more. 2 out of 4 shots on target, 5/9 dribbles completed, 34/44 passes landed; 0 goals, 0 assists. Mixed in with that you have some moments of sheer brilliance and some moments of simple play. That's a very typical Zidane performance in a game like that.
It's important to set the context here: this Juve team ended up finishing 7th the season prior, while they were facing a Lazio team that finished 2nd and 1st between 98-00. So it wasn't an easy game - it wasn't compable to Everton. However it's worth bearing in mind that Juve did finish 7th with Zidane, and at that point Zidane was undeniably a
great player.
Here's a very ordinary performance from Zidane in that very ordinary season.
What the game against Lazio does is highlight is how silly the idea is that Pogba being unable to drag us into the top 4 last season demonstrates his failings compared to his peers. Likewise for the idea that failing to shine in a tight game disqualifies him from being in the elite. Neither of these standards match up to his most apparent comparison, and Zidane is considered by many as one of the very best in history.
If you wanted a direct comparison to Everton, you can look at his game against
Bari in the same season. Bari were just outside the relegation zone and Juve finished 2nd. No goals, no assists, plenty of mistakes, plenty of brilliance. That's not to say Zidane didn't have immaculate performances against the weaker teams, or sparkling performances against the elite...but he certainly didn't all the time. He didn't even do it most of the time. No player ever has.
Many of Pogba's great performances this season are comparable to many of Zidane's in 2000. Similarly many of his ordinary performances are comparable to many of Zidane's in 2000. The difference is Zidane's average performances dwindle in the memory and disappear from the stories and eventually, the image we've created is almost entirely fictional. That's what you're expecting Pogba to be. A player that has only ever existed in your imagination.