How is legislation the only answer? Users can just stop using Outlookif they care that MS is blocking providers. If users don't care and stay on Outlook, why bother legislating it?
First: Most users don't care. From their perspective, its' always the senders fault/problem. And the burden is always on the sender to prove it was actually outlook that dropped the email etc.
Second: corporate & institutional users have no choice
Second: corporate & institutional users have no choice