TL;DR - Jović played 3 games out of 11 where he got more than half hour on the pitch. Only 2 as a striker. Setup a goal in one of them and got 'robbed' of one in the other.
That's the state of pressure and expectations at current Barca and Real:
1. Suarez and Benzema are not world class anymore
2. but if a new guy won't shine right away, he won't get too many chances.
The safer/proven option will continue to play.
And clubs will just move to a new target in the next summer with a hope that a new guy will perform right away. Or, they will move to a 3rd target in the next summer.
In the case of Jovic, he will probably get 1+1 season of chances.
After a first season he will have an imaginary "yellow card" under his name.
And unless if he explodes in the 2nd season, he is dead by a New Year of his 2nd season.
Again, this is what too high pressure and demand for trophies in every game is making from players like Malcom, Paco, Dembele, Jovic.
they are not bad, but a club doesn't have years and years to test whether they will eventually start to play awesome.