I think the key here is that the starting estimate is just that - an estimate. Our understanding of what that means is broken.
If you estimate that your maintenance calorie level is 2000 kcal a day, and you eat about 2000 kcal a day, and you’re still gaining weight, then your estimates are off… so you lower your estimate of your maintenance level. Or maybe your estimate that you were only eating 2400 kcal a day was off, and you were really eating 2600 kcal - so you lower the amount you eat (or improve the accuracy there.)
Either way, the calorie wasn’t broken. We’re just forgetting that our calorie counts in all areas - basal maintenance calories, eaten calories, calories burned in activities - these are all estimates. Our estimates are often wrong at the start, but we should simply revise them, not abandon them.
It think part of the problem is that we’re so used to punching exact numbers into calculators and getting exact results immediately. We take starting estimates and immediately try to calculate exact outcomes! People want to believe that if they’re on a plan that shows a numerical deficit of 117 calories per day, they’ll lose a pound of fat per month*… while forgetting that the 117 is the difference between two much larger numbers (maybe 1950 calories in and 2067 calories out), and BOTH of those larger numbers are actually rough estimates that need to be refined over time based on your specific body and circumstances.
If those estimates are actually pretty good - let’s say, plus or minus 10% of reality - then the variance on the intake is plus or minus 200 kcal (a difference range of 400 kcal), and the variance on the calorie output is plus or minus 200 kcal (again, 400 kcal range), yet we somehow want to believe that the daily deficit between them of 117 is going to be exact!
- PS: I don’t believe in the theory that a 117 kcal per day deficit leads to a loss of a pound a month, for a variety of reasons. But people really want to believe they can just boil things down to simple numbers which tell them they’ll hit a particular goal at a particular time.