Cooperation among consumers can stabilize consumer-resource dynamics, by preventing over-exploitation by individuals maximizing self-interest. While stability in cooperative consumers is often attributed to behavioral interactions, such as punishment of defectors, the role collective environmental modification plays in these population dynamics is not yet known. Microbial biofilms are an important instance of cooperative resource use involving environmental modification. Here, we demonstrate that biofilms can act as a refuge and a source, stabilizing cooperative populations by ensuring positive growth rates for cooperative consumers when rare. Our modeling reveals that stability is achievable across a diverse parameter space, encompassing diverse physiological processes, behaviors, and environmental interactions, indicating multiple pathways to stability for cooperative consumers via environmental modification. For such consumers, the environment is not a static template for ecological and evolutionary dynamics but an active medium shaped by their interactions, opening up novel theoretical and practical directions for understanding and managing cooperative systems.