2 - that's a given, but people feel more secure jailbreaking theirs because the OS or phone vendor never bothered to add in stuff like a proper firewall... oops...
5 - then let's hope the OS manufacturers and hardware vendors both keep up to date. So far, many phone vendors (Verizon, AT&T, etc) tend to be a tad slower with OS updates...
4 - doesn't this point contradict point 3, making one wonder why one would then protect the phone at all? Yeah, some kid might get through it - unless the security is so badly designed (such as face recognition or security bypass features that have not been fully tested...)...
1 - that's a given
