The tragedy can often be avoided by everyone agreeing that destroying the commons is bad
Right, but you’re also creating a prisoner’s dilemma. That is, if everyone agrees to work one way, and you have one person that breaks rules in a way that gets them ahead–and lets say that, in a purely communist society, that ‘getting ahead’ in this instance means that they need to put in less work to have the same result as everyone else, and thus have more time available for themselves–then it creates a strong incentive for everyone to follow suit. You need those outside regulatory bodies with enforcement powers in order to create the disincentive to breaking rules and agreements.
Perversely, farmers often know that what they’re doing is deeply harmful for the environment, but there are strong financial disincentives preventing them from changing. Without both a regulatory structure forcing change on everyone, combined with incentives that make changing affordable to them (such as giving them cash to buy updated equipment to farm in new ways, and ensuring revenue levels), they’re kinda fucked.
Currently doing exactly that. My partner and I just bought a house and a few hundred acres in northern Maine, and will be moving in less than two months. Yeah, winters are cold and long, and yeah, the mosquitos and blackflies suck, but triple digit heat is really rare up there.