Yeah this is another point I agree with too. When you get your first team appearances you have to show something, something that sets you apart from everyone else. I think it's fair to say Rashford and Greenwood showed something different when they were given their opportunities, in a similar vein I think Iqbal has shown something a little different, albeit only in pre-season, and that's coming from someone who wasn't wholly convinced by him at U23 level.
It was pretty obvious from the get-go McTominay and Pereira were a bit shit yet both have wracked up loads of appearances for us, McTominay is on 170(!) which I find mental. Lingard, Tuanzebe, Chong, Williams ... the list goes on. All those players pretty obviously aren't and never were good enough yet got chance after chance.