If they don't make any promises about it, I won't make assumptions about how they should (or shouldn't) handle it.
I'm just going by past experience with other Moto phones. My G5 is still on the January patch. Lenovo hasn't made much of a secret out of their lackluster support. The lack of communication only makes the situation worse. Please understand I'm only talking about security patches, not OS updates.
Android OEMs need to do a much better job at keeping phones patched. An unlocked phone with no carrier to placate with minimal changes to the OS shouldn't take so long to patch.
I knew what I was getting into as far as this goes.