I don't think it's right to write him off already. But imo it's not right either to ask for more minutes for him. Based on his recent performances he simply doesn't deserve it.
We've been complaining to death here about how our standards have been dropped. Rashford must be super pissed off about that situation. He was going to have a chance, a very good chance to bury the match and a hattrick for himself.
A player must earn his minutes, only so his teammates wouldn't feel unfair and our standards wouldn't be dropped. So, unless there's a big injury crisis, which I hope would never happen, imo Ole should never start him again in the PL. At least in the near future. Same with Fred, he had to wait for his chance then grabbed it with both hands.