The problem is centralisation. As most email users move to the 3 or 4 large providers, the incentives for those providers to care about email delivery to the sm

The problem is centralisation. As most email users move to the 3 or 4 large providers, the incentives for those providers to care about email delivery to the smaller players is reduced. Having run my own mail server for about 20 years now, I can absolutely confirm that this is a big problem and getting worse all the time. Gmail is in my experience the worst. And my IP is on no blacklists as far as I can tell. Mail just gets silently dropped, and I only find out about it when my sister gets confused when I ask her why she hasn't responded to my mail.