The name of the game of swimming is to generate the largest thrust force and minimize drag. The speed of the swimmer comes down to a simple formula: speed= distance/stroke times stroke rate. “At constant average speed (v), a balance between thrust force (Ft) and drag force (Fd) should occur: Ft−Fd = 0; hence the power generated by thrust forces (Pt = Ft·v) should be equal to the power needed to overcome drag forces at that speed (Pd = Fd·v)." Thus, in order to get up to an ideal constant speed, the force generated by the thrust force must be greater than drag force. If you are able to minimize drag as much as possible, you are able to get up to a constant ideal speed faster than if drag was not minimized.
quote 1: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0162387
formula: https://www.annualreviews.org/doi/full/10.1146/annurev-fluid-011212-140658
picture: https://qz.com/761280/researchers-believe-certain-lanes-in-the-olympic-pool-may-have-given-some-swimmers-an-advantage/e/
quote 1: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0162387
formula: https://www.annualreviews.org/doi/full/10.1146/annurev-fluid-011212-140658
picture: https://qz.com/761280/researchers-believe-certain-lanes-in-the-olympic-pool-may-have-given-some-swimmers-an-advantage/e/