For starters, absolutely noone who hasn't massive Man Utd blinders on would consider Greenwood in the same bracket as Sancho or Musiala. Greenwood was severely lacking in his overall game, until his last half-season before his massive general talent deficit of being a ... you know.. surfaced. No need to discuss this any further.
Then, I'm pretty sure those 'folk' who recognize Musiala as the generational talent he quite obviously is would have also recognized Sancho's undeniably exceptional talent. Musiala however is performing a more central and difficult role in a much better team, at times with considerable defensive responsibility, and hasn't shown Sancho's tendency to be out of form for periods of the season, if you must compare them.