In Ed Bouchette's mailbag article on the Athletic this week someone actually asked him about turf at Heinz Field. The first sentence of his response says it all.
"I believe you’d find the players enjoy the real grass at Heinz Field more than any artificial surface in the NFL."
Unless and until that ever changes, there is no chance at all that they will put turf in at Heinz. The players hate it. Today's turf is better, but there are still more injuries on it than on grass. Guys feel worse longer after playing games on turf than grass. It's a fantasy of some fans, for some reason. It isn't going to happen.