because of the three tier system, manufacturing breweries have to be on a their own tier apart from wholesale distributors, so forming a co-op would be illegal. Manufacturing brewers ARE able to self-distribute, but their 250 BBL/yr distro cap would go down to 40K. Guess what happens if a brewery in TX goes over the 250K cap and also sells on-premise in Texas? The brewery would have to sell it to the wholesaler only to buy it back for onsite sales, even if the beer never leaves their brewery in the first place. There are only a handful of breweries in texas like this, including Karbach (owned by AB-Inbev), Revolver (Miller/Coors), and Independence (Heineken, sorta). They are somehow grandfathered in (whoa, wonder why, maybe because BIG DISTRO is basically in bed with BIG BEER?) and don't have to do that. But there is one craft brewery who falls in this category: Oskar Blues in Austin.
Brewpubs are considered retail and can sell to-go and also self distro up to 1K barrels, so they are on that 3rd tier.