^^^ Most cruising cats are underpowered most of the time (maybe all the time with careful owners). Typically they're going to find their upwind VMG at pretty broad apparent wind angles because there isn't enough power in their rigs. Efficiency (eg lift:drag) plays into it but I think it's secondary to lift for the "typical" cruising cat. Adding more sail power adds cost and risk beyond what is ideal for the service.
FWIW, my experience on my 40ish foot cruising cat with good foils is that my upwind vmg v monohulls improves as the wind gets up as long as I'm willing to sail nearer and nearer the edge of stability. The thing is, sailing like that isn't safe or relaxing.