Muffin Fan Installation Norcold 1200LRIM

I am a little confused about something. I remember the fridge my parents had in their second motorhome. OK, we live in the midwest, but that fridge would freeze the refrigerator, if you set it cold enough. It did not have any fans. I do remember traveling to Florida once, and the fridge was still not a problem. Why do fridges now need fans, when they never needed them before? The Dometic in my coach cooled very well, and did not need a fan when it was new. It was only after I replaced the cooling unit, that it was marginal in hot weather. I have since replaced the cooling unit again with one of the "Amish" units. It also does NOT cool as well as the OEM unit, although seems to be better than the previous unit. Seems if these cooling units were built right, they would not need fans. Yes, I am considering putting a fan on my current unit, but I would rather it just worked as well as OEM.