Questions to think about:
Are the factories where the bricks are molded the same as where the pieces are bagged and the boxes are packed?
Is there only one factory where boxes are packed?
Are the warehouses in the same location as the factories?
Depending on how these things are distributed, very few people may have a complete picture of the state of a given set.
Town Hall contains some unique (or semi-unique) parts. Say you are the mold-worker who made a batch of 61287pb001/61287pb002 four years ago. Do you have any idea how many of those went into copies of 4191, how many have gone into copies of 10224, and how many are projected to be needed for 70810? Do you know how many are still sitting in warehouse shelves? Do you know if another worker in another factory made a batch?
Say you are the worker who packed a shipment of 10224 a year ago. Do you have any idea what the current inventory situation is world wide? Would you know if another shift (or another factory) produced a shipment in the past few months?
Just because any individual worker can think "Hmmm, I haven't seen X in awhile" doesn't mean conclusively that X is going away immediately. Not unless that worker also knows the worldwide inventory situation. Maybe X hasn't been produced because it is a dog of a seller that is setting on warehouses gathering dust?
Another factor (not saying it applies here, but just think about it) is that molds wear out or break. Part 61287 is used in only 3 current productions sets: 10235, 10224, and 70810. If the mold for that part was out of commission, but a finite supply of parts that was estimated to cover lifetime demand for 70810 was available, it would be a rational business decision to analyze the cost of a new mold, expected profit for continuing 10235 and 10224, and decide to discontinue those two sets and hold all remaining parts for 70810.
Just saying that very few people in the company probably have a world-view of the factors involved before a product is stopped.