IIRC you can still log into a lapsed Workspace account, but the core "business" products like Gmail, Docs and Meet are completely disabled until you reactivate your subscription. The rest of Google still works to the extent that it ever did under the weird Workspace limitations.

You cannot migrate a Workspace account into a regular Google account, you're stuck with Workspace forever unless you start over on a brand new account.

I honestly believe that last point is the reason people still have their free grand-parented in workspace accounts. Google went to close them down realized they didn't have a graceful way to let people keep their paid for apps and realized the engineering time to create a workspace to consumer migration was worth much more than any costs associated with those accounts.