We know you are patiently waiting for this feature. This feature is being implemented in stages. Fast tenant switching is currently in testing both internally and with early customers. We expect to release to the public in the Fall. I’ll post an update once it’s rolling out.
Full multi-tenant, multi-user support will be added after fast tenant switching.
I agree with @Bertie. To switch orgs is a very time consuming exercise AND what is really needed is that I can see activity in all the teams I'm affiliated to via my multiple identifications (volunteer groups, businesses, friends) without these "orgs" needing to be aware of the other "orgs". I should see and respond to the feeds without having to switch orgs just to see if there has been any activity.
Hope that helps refine the requirement.