Yeah his level has dropped recently, but the good thing is that even then he's been on the scoresheet while playing poorly, same as Rashford. Now that Rashford is out and he's the only real threat, that may not be the case anymore.
When Martial was out, Rashford only scored 1 non-penalty goal, and I think 2 goals in total. In that time period, we didn't score more than 1 goal in any game. One he was back, we scored three, with him and Rashford getting on the scoresheet.
Of course those sorts of things will be forgotten since it was a while ago, but at the time people were very frustrated with Rashford, wanting to "burst his bubble". He became more consistent with Martial playing alongside him, without him he struggled for sure.