Some activities are much easier than others to start learning. On holiday in the Isles of Scilly with my sister and her family, the children tried various watersports. Kayaking and sailing are easy to get started on, because you sit in a stable boat and if you do absolutely nothing, nothing bad happens immediately. Windsurfing is much harder, because the first thing you have to do is balance on the board and pull up the sail, which are both quite difficult; you are then in a dynamic situation requiring active balance and control immediately.
On a more topical note, I imagine that starting as a 100m sprinter is relatively easy (you just run as fast as you can, right?) but starting as a pole vaulter must be very difficult.
I think tower bell ringing is in the same category as windsurfing. You have to get to grips with the dynamic control of the bell before you can even ring rounds, and this usually takes several lessons. Learning on smaller bells can shorten the process (many people have reported success in teaching basic handling very quickly on mini-rings, although possibly with an over-the-balance style which, to my mind, is not really tower bell ringing as we know it) but it still takes a while to be able to ring rounds unaided.
Handbell ringing, in contrast, is much easier at the beginning. Striking the bell is almost trivial and nearly anyone can ring decent rounds with only a little practice. Our experience with the Mount Vernon Handbell Club has shown that children can get as far as plain hunting a coursing pair fairly quickly, and this lets them see what change ringing is all about.
Maybe teaching handbells can be an effective way of recruiting tower bell ringers too; if people find the mental challenge of ringing methods interesting enough then they might want to move on to the physical challenge of ringing tower bells.