Why three high-end destroyers do not make a high-low mix

Would a Type 052D, Type 055, and modernized Zumwalt combination make the best high-low destroyer force?

No. All three are high-end combatants, so the proposal is a high-high mix rather than a fleet balanced across high, medium, and low capability and cost tiers.

The proposed ships are powerful, but the force-structure label does not fit. A genuine high-low mix needs less costly ships for the middle and lower tiers, whereas Type 052Ds, Type 055s, and Zumwalts all sit toward the demanding end of procurement and combat capability. Type 45 or Hobart-class ships offer a closer economy-sized destroyer comparison while remaining capable warships.