I am fairly certain the answer is no. My current company does not require archiving. In a previous job, I worked at a big auto company that had a very structured records retention policy. Email was considered "transient' data with a life of 12 months - no long term storage intended.
Records retention policy is a mixed bag because litigation is so common. In the event of a lawsuit, the discovery process can require a search of your emails and then use them against you in their suit. Based on what I learned at the auto company, the best process says (a) have a records retention rule which includes a purge schedule, and (b) make every effort to ensure that things are purged at that date. Of course, purge rules can be suspended by court order.
The best way to get into trouble is (a) fail to purge in accordance with your records policy (or not have a records policy at all, (b) get sued, then (c) decide to do all your neglected purging.
For a service provider, I would suggest that records retention be explicitly specified by your customer as part of their contract.