It's easy - mobile devices are end-user devices. They should be locked down. Apple gets this right.
If you want to program to your hearts content, buy a general-purpose computer. That's what I do if I want to program at that level. I have programmed at that level and even lower:
http://www.textfiles.com/bitsavers/pdf/burroughs/B1700/MIL_MicroImplementationLang.pdf
I don't need to program a specific-purpose device for that thrill. The only people that want that level of control are malicious hackers.