Android prepares to only support Seamless Updates, but Samsung could still avoid it
Android introduced support for Seamless Updates quite a long time ago at this point and, while it's seen adoption from most, Samsung stubbornly refuses to move its devices to the A/B system. Android is now moving towards a future where A/B Seamless Updates are the only supported update mechanism, but that may not be enough to stop Samsung.
Ben Schoon at 9To5Google
The fact Samsung hasn't embraced Seamless Updates yet is utterly baffling. It's better in every single way, and there's little to no downsides one can think of. I hope this little nudge gets them to finally get their act together.