I compost at home, and I “toss” my pile at least weekly to get more oxygen in the pile and accelerate the breakdown of greens and browns into compost. As I understand it, everything in my pile would EVENTUALLY break down if just piled up, but composting is done semi specifically to take advantage of prime conditions for the breakdown process. All that to say, it definitely doesn’t breakdown as quickly/effectively in a landfill due to lack of oxygen