Yes, I see that but doesn't it make more sense to play those out of poition who have something to show than "punishing" the one who currently delivers?
And while Rashford might also be best on the LW, he can definitely do a job on the right wing as well. Given your vacancies in this position, you just need him to do the basics and complement the squad, not play on a world class level himself or excel individually. And I'd argue that Rashford's skill set is much better suited to playing with his strong foot outside than Sancho's. He can hold the line and beat defenders by accelerating past them and cutting back, more so than Sancho who needs to cut inside to work his magic. And then the next goal should be to sign a counterpart to Sancho on the right, ideally left footed.
People would never entertain the idea to play Messi on the left or Neymar on the right to complement worse players than them.