Most people at a gym are not the fitness-focused people you're thinking of. Most are just white collar workers who need some exercise. A typical American diet already has an embarrassing surplus of protein, there's very little gear that your average person is going to need (active clothes can just be shorts and t-shirt, maybe swim trunks, and a pair of shoes), and IMO most people don't need a trainer for more than a couple of sessions to show them the ropes.