[jupiter2]

Late response: I'm having a hard time understanding your reasoning here.

A less generic comparison is Apple. Apple builds it's own devices and supports them.

If I buy an ASUS Tablet, I'm not expecting them to provide security updates to Lenova or Samsung Tablets. I am expecting them to support their own devices. They have everything they need - they built the devices themselves.

Similarly, if I buy an phone that's been purposely tweaked by AT&T, working with Samsung - I expect that they are more than able to provide security updates but are simply unwilling to do so. They have all the tools (drivers, access, etc) they need.

You're looking at the general Android landscape. It's a question of holding the device makers accountable. Providing security updates for devices you build yourself, with drivers you developed yourself (or through a partner) isn't an issue - it's pure (litigable) greed.