Not only that, but by buying from Apple you are subsidizing the practice anyway, so that next time they can develop an even harder to crack version. Aside from that it's a boondoggle, an economic waste to build protections just to crack them. Better to buy hardware from vendors that allow (or tolerates, such as Samsung) rooting and installing custom firmwares.

It is kinda impossible today (compared to golden days of iPhone OS 3.1 - I must've freed a good 50 iPod touches back then (for my friends)!). You have to wait a few months after any major or even point release, and jailbreaking new devices might take up to 7 months (I think that was the case for iPad 3)!