I could be wrong but I think qualcomm is the biggest obstacle for google in supporting older phone versions.

they won't ship updated drivers for new android versions for old phones.

The difference being that since every app dev expects iphones to be on the latest ios version, as soon as your phone goes out of support it will become obsolete quickly. Android has a larger install base of users on old os versions, so you can expect support even if you aren't on the latest one. New ios versions usually have the disadvantage of being poorly optimized for older models, and I personally have never cared much about the new features. So staying on the old os version indefinitely might be a better option as long as apps still support it.

While I appreciate that some phones can be supported by the community, I think it's unreasonable to expect that the community continue support in place of OEMs. Especially ones like Google, that can set the tenor for the entire Android ecosystem.

No SafetyNet, so useless for some of us.