I think modeling has a place. It can help me recognize where efficiencies may be gained by pointing out things that might be problems. Can and may aren't will.
I suspect that some folks think that the mays and mights are as good as "will".
I am forced to camp from time to time. I have a sleeping bag rated to 20F. It is rare that I zip it up. Normally it just lays on top of me.
A tent with few vents will keep you ever so much warmer than a building with open walls.
A building with open walls will keep you ever so much cooler than a tent with no vents.
Those are the same statements. In summer, the bottom is better. In winter the top is better. This may sound so obvious as to be foolish to even talk about. I suspect that many of these folks have never integrated this information though.
A piece of 1 mil plastic will turn that frigid Adirondack into a toasty oasis (toasty is relative), but it is the difference between getting completely mummified in my sleeping bag or just lying under it.
Windows are tradeoffs. Security vs light. Vs airflow. Vs. egress. Vs. Comfort. Eventually you get to very marginal returns. If your energy bill is $800/month, there is lots of room to make improvements. If the energy bill is $200, things get a little more uncertain. $100? We now might want to look at things that will use more energy to make our lives a little easier.