More is better only works to a point. At least one study was done that determined excessive increases in stack (60 mm in this study) didn't improve running economy (metabolic power), however, the study was done on nitrogen infused midsole and EVA midsole shoes. I would submit that different foams, plate configurations, soled geometries, surfaces used on, etc., should have different optimal stacks.
Effects of midsole stack height and foam on the metabolic cost of running
Montgomery Bertschya, Herlandt Linoa, Laura Healey and Wouter Hoogkamer
Methods:
Two sets of weight-matched
footwear conditions were worn (part A: 30mm
EVA, 40mm EVA, 60mm EVA; part B: 30mm
EVA, 30mm NITRO, 60mm NITRO)
Results
Within the EVA midsole material (part A), larger
stack height led to a non-significant increase in
metabolic power (0.4% increase per 10mm,
p=0.12; Figure 1). Within the NITRO material
(part B), larger stack height led to a non-significant
decrease in metabolic power (0.13% decrease per
10mm, p=0.052).