>But in reality, Samsung (and the other Android OEMs) cannot compete with Google and its unique control over hardware and software.

Yes, they can. We are talking about applying provided security patches to source code, and then releasing a new version of their OS. For patches that have existed for months. The time from patch to release should be on the order l of days from receiving the patches to having a validated OS release with the fix being sent to users. It's not the control of Android which makes Google possible to patch their Pixel branch of AOSP faster than Samsung can patch their own. It's that Samsung doesn't care about prompt security fixes so they don't allocate engineers to do the work.