One of the issues with self-hosted email from a home server is that you get an IP address that’s dynamically assigned by your ISP, and sometimes spam filters will blacklist IP address or IP address blocks. I used to host my own postfix server (and have a guide here if anyone’s interested), but one day I rebooted my router and was assigned a new IP address, and suddenly emails I sent to gmail recipients went to spam. I’m happy fixing issues that I’m able to fix, like setting up DKIM correctly, but this thing that was outside of my control was just too much for me.
But by all means, please fight the good fight! I wish everybody with the technical inclination would at least attempt to self-host, since a larger user base would keep us from having such a siloed monoculture.