Question
Will the archived emails disappear when an account is deleted due to retirement or other reasons?
Answer
The archived emails will not be affected by account deletion.
Google Workspace / Microsoft 365 forwards emails for archiving to the Email Archive at the time of sending and receiving emails.
(Emails for archiving are generated separately from the actual emails sent and received.)
Since the Email Archive stores these forwarded emails, it is not affected even if the account is deleted afterward.
Note that the email retention period is the period you applied for at the time of service contract.