It's all about function and simplicity. Take a Massey Ferguson 1100 (1964 - 1972) or 175 (1964 - 1975). You could tear them down to the frame with two hammers, a good (big) wrench set and enough time. I have, and do. I currently run one of each, today, as work machines.
Now, everything is computerized and requires a degree in electrical engineering to figure out. That's not me being a Luddite wishing for better days, it's a fact.
I can fix mechanical breakdowns in the field, no matter how complicated. Those machines are simple to maintain, cheap to run, and are unbelievably reliable. The process to diagnose and solve issues is as simple as finding the part that is cracked or fell off.
My neighbor has a John Deer 5E something or other utility tractor. Same horsepower as the 1100, and smaller, which is nice. BUT, we can't fix a fried circuit on the throttle control - hell, we're lucky to find it without needing to call out the implement dealer.
It's that; simplicity. Those mega-tractors and all of the new bells and whistles are great for corporations and large-outfits who can afford to have a machine down for three weeks while you wait for diagnosis and repair.