That's not really accurate. Displavement hulls are more efficient at lower speeds for the same displacement (i.e. payload mass), but at higher speeds, the speed

That's not really accurate. Displavement hulls are more efficient at lower speeds for the same displacement (i.e. payload mass), but at higher speeds, the speed-power relationship of planing hulls flattens allowing for MUCH higher speed transits, whereas the power requirements for displacement hulls just continues to skyrocket with increased speeds (1). Freighters are generally displacement hulls because they carry thousands of tonnes of cargo. This sizable displacement would make it impractical for these vessels to "get up on plane" (assuming their hulls were shaped like planing hulls vice displacement hulls). You can simply carry more payload in a displacement hull than a planing hull. Planing hulls like to be lightweight. It's not impossible to make a planing freighter, just impractical - and all of that inertia and mechanical stress on the hull structure while traveling at high speeds would be very difficult to design against, not to mention very difficult/unsafe to amneuver in a sea lane or inclement weather. There are certainly high speed ferries, which are generally catamarans (for added stability) with similar speed-power characteristics to planing hulls, but those are still carrying relatively lighter cargo (humans, some cars) over shorter distances compared to fairly dense bulk liquid/material/container cargo transiting accross oceans. 1. https://images.app.goo.gl/Yn3znGUBgiM9jkB4A https://images.app.goo.gl/Yn3znGUBgiM9jkB4A