I’m curious to know how you could know if any emails you send are getting silently dropped. Do you check with the recipient again and/or through other modes of communication?
One of the server sends and receives emails for the forum, sometimes up to 1000 messages a day. It was set up 5 years ago.
Maybe this is a serious issue when you use popular VPS providers/IP ranges, but I use smaller providers, and just don't remember any email-related issues everybody are talking about.
For me, email self-hosting as easy as installing mail-in-a-box (for sending+receiving) or just plain exim/postfix (for sending only), with proper configuration.
We also have receipt tracking, which isn't perfect, but shows a >93% open rate.
We did have an issue delivering to a specific provider, but that was resolved by updating our DKIM with a more robust key length.