They absolutely restrict their own production. Have you ever been to one of these things before? There are probably a few maple syrup producers out there trying to scale up, but for the vast majority, it’s a lifestyle/supplemental income kind of thing. They tap some trees, invite everyone over and charge a few bucks for pancakes while they boil their syrup, and then move on to other things when the ground thaws. The University of Vermont has been trying to set up sap production as a competitive form of agriculture but people just aren’t interested. Literally every syrup producer I’ve met was in it for the romance.