So, if Goretex and eVent are breathable does that mean when they are put in shoes they are just as breathable as in coats? Well, the membrane is as breathable but generally your feet will feel hotter than in a pair of non waterproof boots. The reason is quite simple, your feet generally get very hot and achy, especially after a long days walking and the boots do not have anywhere for the heat to go.
The only hole in your waterproof boots in filled with your foot and the hot air cannot escape from there. The waterproof membrane is breathable but there is soo many layers of padding, membrane, leather or fabric and plastic heel cups that its hard for the moisture vapour to escape.