Because Pretty Girls was riskier. A duet with controversial Queen of Rap Iggy who was at the peak of her hate and lyrics that alienate heterosexual males, a large portion of the GP.
Make Me is a lot safer and conventionally Britney and would do well based on "comeback" hype alone, has sexier single artwork, being paired with a non-controversial rapper and not completely alienating heterosexual listeners.
Because Pretty Girls was riskier. A duet with controversial Queen of Rap Iggy who was at the peak of her hate and a lyrics that alienate heterosexual males, a large portion of the GP.
Make Me is a lot safer and conventionally Britney and would do well based on "comeback" hype alone, has sexier single artwork, being paired with a non-controversial rapper and not completely alienating heterosexual listeners.