I've read it. I worked at Apple in the 1980s and experienced Steve in real time... You are correct that he did not want people mucking around in his creations, but his stance on jail breaking was pretty clear. Every exploit that could be used for jail breaking was a hole in his operating system that was intolerable. Making iOS impossible to jail break was going to be difficult. Punishing jail breakers to make it less attractive was always an option, however to date they have not taken any action other than refusing to service any devices that show up in the store - and possibly disabling iBooks intentionally on jail broken devices...
He lauded the Mac's security over Windows at every opportunity, and was thrilled that iOS was closed and secure where Android was easily rooted and had hundreds of exploits in the first 6 months... If jail broken devices ever become a large community, and jail breaking opened up exploits, iOS would lose some of its shine as a virus proof OS, and he hated the thought of that happening.
Cook will clearly honor Steve's vision for a while, but whether or not he shares his obsession is to be seen.