If a club doesn't keep at least a couple of trainer planes on hand it's really tough to pull new people into the hobby. My club, which Thomas B is also in, uses trainers that the club members own. Several of the instructors have kept their own trainers or picked up used ones pretty cheaply. I believe one was actually built and donated by a local hobby shop a few years ago and owned by the club, and I learned on it. I'm not sure if it's still flying though. I worked with every instructor the club had at some point during my learning, and I flew basic high wing trainers, a Goldberg Tiger II, a .40 size Cub, and my own Cessna 182 as a student. Opjose definitely has the sweetest club instructor fleet I've ever seen, but it need not be as fancy as that to be able to teach newbies who don't have any equipment yet. Any trainer or docile sport plane will do provided that there is a buddy box available for the instructor's radio.
The club has the attitude that anyone who shows up on training night gets to fly as long as there is a an instructor and a plane for them to fly with. It's club policy that no one pays for training, not even for fuel. There have been a few that were regulars at training who had no intention of ever getting their own equipment and doing the hobby themselves (mostly kids whose parents wanted the free entertainment for them),but most don't dedicate the time beyond the first try if they aren't serious. But the way the instructors look at it, even those who aren't serious are getting to see what the hobby is all about, so they are being educated that it exists and is enjoyable. You never know how many will return to it a few years later when their finances or schedules allow them to. Having an organized and free training time is the main thing a club can do to promote the hobby. Otherwise all of our growth just comes via established modelers having children who get into it with them.