No, they shouldn’t be archived. I say that because technology can change. At some point they added a new sort method which favors more recent upvotes and it helps more recent answers show above old ones with more votes. This can happen on very old posts where everyone else might not use the site anymore. We shouldn’t expect the original asker to switch the accepted answer potentially years down the line.
There’s plenty of things wrong with SE and their community but I don’t think this is one that needs to change.