Their mistake was in framing it as collective bargaining. What if they put the owner in the group with them and brainstormed ways to allow everyone to prosper. Casting it as a zero sum interaction--we want more from you and unfortunately you get less--rarely works as well as shared problem solving. At an individual level if they had investigated other opportunities and reported back practices from other employers that matched what they were asking for it would strengthen their case that it would be hard for the employer to attract new employees with their current set of policies.

You have to look at it as a dynamic system or ecosystem. "Us against them" is rarely the most effective framing.