This is outright stupid marketing, "All your data are belong to us", pay monthly for continued access to it, complete garbage.
There are VERY valid security reasons to offline archiving, as well as backup and retention policies.
So what now, when a users' mailboxes get compromised... You know, BEC only being the #1 cybercrime vector globally, then the criminals have to have access to all your years of data if you personally want to pay Micro$oft for the same luxury?
Are we actually supposed to upload years of stored data BACK into our mailboxes!?
Or run thunderbird over IMAP?
Micro$oft has been called many names over the years for decisions like this, ransomware now resoundingly makes that list.