If $5/(user * month) for google suite is imposing cash flow problems then you should fix that rather than spend your time administering your own email server.

FWIW (this is merely a single example): my current company (which includes two ex googlers among the five founders) specifically uses no google infrastructure (no gmail, no google docs, no cloud, photos, hangout etc).

Actually I exaggerate: three of us use google search.

Edit: Someone asked why but their comment was downvoted dead so I am amending my comment.

There were three reasons; privacy, features, and dependability.

The privacy one is well discussed elsewhere. Apart from paranoia (won't get into that), there are UX issues. For example on the shared google docs for our local Boy Scout troop I've seen patient's files accidentally shared by physicians, internal corporate documents from some Fortune 50 companies and the like. Clearly nobody shared those on purpose!

For features: we certainly don't want to build a dependency on chrome (the new IE). One of the team had to move a google acquisition from AWS to gcp and swore never to use the latter again. Gmail doesn't follow standards (e.g. IMAP, adding AMP to mail)...the reasons go on. many products simply aren't best in class (e.g. zoom works much better for us than hangouts); others are (google docs / sheets may not be best-in-features but seem to have the best simultaneous editing, better than Apple or Nextcloud/Collabra when the network is flakey)

For dependability: one is of course products and features getting randomly cancelled. The other is cases where one account gets cancelled and it wipes out all connected features. These stories are scary; some have appeared on HN.

All in all it's not worth the risks.

Thanks for your insights. I used google suite only as an example, there are a great variety of other services available for email, etc, some with much better privacy features. My main point was that maintaining your own infrastructure is much more expensive than using off-the-shelf services, so the price argument further up the thread isn't really justified.

Email is unlikely to be the only service you need. Add github and your at 14$ a month per person. Keep going and it really does add up fairly quickly.