> it's an entire lifestyle

You might be overthinking this, although I understand how it can appear that way for someone on the outside looking in. Your local gym probably costs less than your Netflix subscription, if you don't already have a free gym in your apartment building. You don't really need anything else other than looking up some routines on reddit.

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.