WH904,
Since you have an interest in what/why subscribers are failing to renew I'll be blunt and mention that the appalling cult of 'me, me and me' that surrounded the new editor a few years ago had a major influence on my choice not to renew my subscription.
The price is fine, delivery was prompt but I despaired of reading all about the editor and how wonderful he was (is?). The articles became a bit samesame, there are never enough on rotary wing
but overall I would say that the change of editor sealed my decision.