Firstly januzaj season under Moyes is no way near comparable to what Martial produced last season, secondly Martial was bought for huge money because he was showing great form at Monaco and many teams were after him for that, thirdly even this season he has shown more good and great form only for the manager to bench him the next game, who knows what would have happened if the manager gave him more supports and trust! Even if we only consider this season, I don't actually think that Rashford has shown great things to label him a better talent than Martial, Rashford have benefited from the trust the manager puts on him! Even before the season started, Jose was only talking about Rashford and almost not about Martial who was by a large margin our best outfield player the previous season! That purely shows who was the manager's prefered player!
But let not derail the thread and go back to the comparison with Perreira; did you really think that Rashford is more skillful than him? I don't think so and will not let some random stats full my view on both players! As I said, Rashford is a good player and has an eye for goal and he's pacey, that is almost his full set of skills; but Perreira has more attributes into his game, he's a good dribbler, a good crosser, has a good long passing range, he can play good shorts pass and good one twos, he has the ability to control games playing like a deep laying midfielder, he can play many position across the field and be good at all of them (just for comparison Rashford was awful playing in the wing and was constantly running the ball out of the field), and he can score wonderful goals too.
Anyway, as @Arthur Friedenreich said it, people are creating an imaginary version of Rashford that is different forms the reality; the stats even showing that Perreira is having a better season playing for a relegation team; add the fact Rashford scored most of his goals playing as a pure 9 while Perreira has scored his playing in many different positions, I'd say Perreira have been better player.
Martial has clearly not been as good as last year. He has only 9 fewer appearances than last year and only half the goals. In a nutshell, he has regressed, and I doubt anyone would argue with this. And who knows if he has worked as hard in training to justify playing more than he has. One thing is for certain, he will not play much next year if he doesn't turn the ship around.