Why orgs use Exchange/M365:
Active Directory integration —- Single sign-on, group policies, user provisioning — deep Windows ecosystem lock-in
Calendar/scheduling —- Room booking, shared calendars, meeting invites “just work” across Outlook clients
Compliance/legal hold —- eDiscovery, retention policies, audit logs — enterprise/legal requirements
Familiar UI —- Users know Outlook; retraining costs money
“Nobody gets fired for buying Microsoft” │ CYA procurement — vendor blame-shifting
Bundling —- M365 = Teams + SharePoint + Office + mail — one contract, one throat to choke
The real lock-in:
- Calendar sharing/delegation is the stickiest part
- AD/Entra ID integration means email = identity = auth
- Migration costs (data + retraining + political capital)
What’s NOT compelling:
- Reliability (see: today)
- Simplicity
- Cost (per-seat adds up)
- Privacy
- Standards compliance (IMAP/JMAP support is an afterthought)
Truth: it’s inertia + integration + procurement laziness, not technical superiority. Exchange is a 1996 architecture with 30 years of cruft.
Linux works as an alternative. We’ve been running it since 1993.