Imagine a world where you had to buy a new desktop because the vendor provided you with Windows XP service pack 1 but decided the machine would no longer be supported? That situation does not exist, thankfully, because PC vendors never had the nerve to lock owners out of their own property.
The cell phone industry still thinks they should control every little interaction on the handset, forcing their bloated UI overlays, restricting features, and nickel and diming customers. I refuse to entertain the notion I should be giving these people more money for the sole purpose of formalizing their control my property.
I run ICS on a Samsung Galaxy S. Samsung officially will not support it because their resource intensive "improvement" called TouchWiz can't run on the older handset when ported to ICS. Meanwhile some kid, for free with spare time, managed to build a fully functional ICS version I run without issue.
At this point in time, locked bootloaders only exist to keep customers on the hardware upgrade treadmill. It needs to stop.